bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordination and Coupling of OH‐Functionalized C2 Units at a Single Metal Center: The Synthesis of Alkynyl(Vinylidene), Alkynyl(Enyne), Bis(Alkynyl)Hydrido, Enynyl, and Hexapentaene Rhodium Complexes from Propargylic Alcohols as Precursors
Authors: Werner Helmut , Wiedemann Ralf , Mahr Norbert , Steinert Paul , Wolf Justin
Published: July 2007

The reaction of [Rh(η3‐C3H5)‐(PiPr3)2] (1) with HCCCH(Ph)OH yields the alkynyl(vinylidene) complex trans‐[Rh{CCCH(Ph)OH}{CCH–CH(Ph)OH}(PiPr3)2] (2), while from 1 and HCCCPh2OH the alkynyl‐(enyne)metal derivative trans‐[Rh(CCCPh2OH){n2‐(E)‐Ph2(OH)CCCCHCH–CPh2OH} (PiPr3)2] (3) is obtained. On treatment with 1‐alkyn‐3‐ols HCCCR2OH (R = Me, Ph, iPr), the highly reactive π‐benzyl compound [Rh(n3‐CH2Ph)(PiPr3)2] (4) yields the five‐coordinate complexes [RhH(CCCR2OH)2(PiPr3)2] (5–7) of which those with R = Me and Ph can be converted to the alkynyl(vinylidene)metal isomers trans‐[Rh(CCCR2OH)(CCH–CR2OH)‐(PiPr3)2] (8, 9). Compounds 8 and 9 react with L′ = CO and isocyanides by migration of the alkynyl ligand to the vinylidene unit to give the enynylrhodium(I) complexes trans‐[Rh{n1‐(Z)‐C(CCCR2OH)CH–CR2OH}(L′)(PiPr3)2] (10, 11: L′ = CO; 12–15: L′ = CNR′). Cleavage of the Rh–C s̀‐bond of 10 with CF3‐CO2H affords trans‐[Rh(n1‐O2CCF3)‐(CO)(PiPr3)2] (16) and the enyne (E)‐Me2(OH)CCCCHCH–CMe2OH (17). Compounds 5–7 react with L′ = CO and isocyanides to give the octahedral 1:1 adducts [RhH(CCCR2OH)2(L′)(P‐iPr3)2] (18–20 and 24–27), of which the CO derivatives 18–20 readily eliminate HCCCR2OH to yield trans‐[Rh‐(CCCR2OH)(CO)(PiPr3)2] (21–23). On treatment of 6 or 9 (R = Ph) with Al2O3 in the presence of chloride ions, besides trans‐[RhCl(CCCPh2)(P‐iPr3)2] (28) the hexapentaenerhodium(I) complex trans‐[RhCl(n2‐Ph2CCCCCCPh2)(PiPr3)2] (29) is formed. The kinetically preferred isomer trans‐[RhCl(n2‐Ph2CCCCCCPh2)(P‐iPr3)2] (33) has been prepared from [RhCl(PiPr3)2]2 and Ph2CCCCCCPh2; it rearranges smoothly at room temperature to the thermodynamically more stable isomer 29. The molecular structures of 7 and 29 have been determined.
Se2NBr3, Se2NCl5, Se2NCl‐6: New Nitride Halides of Selenium(III) and Selenium(IV)
Authors: Lau Carsten , Neumüller Bernhard , Vyboishchikov Sergei F. , Frenking Gernot , Dehnicke Kurt , Hiller Wolfgang , Herker Martin
Published: July 2007

Se2NBr3, a planar molecule shaped liked dividers, was formed by the reaction of SeBr4 with N(SiMe3)3, which reduced the selenium to the trivalent state. Under the same conditions, Se2NCl5 was obtained by the reaction of SeCl4 with N(SiMe3)3, retaining the tetravalent state of selenium. The molecule is formed by two edge‐sharing pseudotrigonal bipyramids with selenium as their central atoms. Se2NCl5 reacts with PPh4Cl to form the Se2NCl‐6 ion by the addition of a Cl‐ ion to only one of the two selenium atoms, resulting in pseudooctahedral coordination of this atom. Ab initio calculations for all the compounds reported confirm the experimentally determined structures.
Polystyrene–Poly(propylene imine) Dendrimers: Synthesis, Characterization, and Association Behavior of a New Class of Amphiphiles
Authors: van Hest J. C. M. , Delnoye D. A. P. , Baars M. W. P. L. , Elissen‐Román C. , van Genderen M. H. P. , Meijer E. W.
Published: July 2007

A new class of amphiphilic macromolecules has successfully been synthesized by creating well‐defined diblock copolymers of polystyrene (PS, Mn3.2 × 103, Mw/Mn=1.04) with poly‐(propylene imine) dendrimers. A poly‐styrene core molecule with a primary amine end‐group was prepared by a quantitative three‐step modification procedure of acid‐functionalized polystyrene. On this core molecule, five different generations from PS‐dendr‐NH2 up to PS‐dendr‐(NH2)32 were constructed in high yields. The molecular structure of the block co‐polymers was analyzed in detail with NMR and IR spectroscopy and electrospray mass spectrometry. With conductivity measurements and monolayer pressure–area isotherm determinations, we observed generation‐dependent amphiphilic behavior. Dynamic light scattering and transmission electron microscopy showed that amphiphile geometry had a distinct effect on aggregation behavior; this is in qualitative agreement with Israelachvili's theory. Critical association concentrations determined with the pyrene probe luminescence technique were as low as 5 × 10‐7 M. The amphiphiles presented here, therefore, show a resemblance to traditional block copolymers with regard to size and stability, and are similar to surfactants with respect to tuning of the shape.
Helical Complexes and Beyond
Authors: Williams Alan
Published: July 2007

Helical complexes have been much studied as examples of self‐assembled supramolecular units. Their structural features are analysed in terms of the metal ion, the binding site on the ligand and the bridging group linking these sites. Understanding these elements allows the controlled assembly of multicomponent systems. Preliminary results show the complexes to have high stability, arising from the inertness of the self‐assembled species.
Organic Fluorine Hardly Ever Accepts Hydrogen Bonds
Authors: Dunitz Jack D. , Taylor Robin
Published: July 2007

Statistical analysis of structural data and detailed inspection of individual crystal structures culled from the Cambridge Structural Database and the Brookhaven Protein Data Bank show that covalently bound fluorine (in contrast to anionic fluoride) hardly ever acts as a hydrogen‐bond acceptor. The weakness of covalently bound fluorine as hydrogen‐bond acceptor is backed by results of new molecular orbital calculations on model systems using ab initio intermolecular perturbation theory (IMPT), and is in accord with results of other physicochemical studies and with the physical properties of fluorinated organic compounds. Factors influencing the strength of hydrogen bonding in extended systems are discussed.
The Importance of Magnetic Coupling Through Atoms with Large Spin Densities—Structure and Magnetic Properties of meso‐Tetrakis‐(4′‐tert‐Butylphenyl)Porphinatomanganese(III) Hexacyanobutadienide, [MnIIITtBuPP]+[C4(CN)6].‐
Authors: Sugiura Ken‐Ichi , Arif Atta M. , Rittenberg Durrell K. , Schweizer Jacques , Öhrstrom Lars , Epstein Arthur J. , Miller Joel S.
Published: July 2007

[MnIIITtBuPP]+[C4(CN)6].‐ · 5PhMe [MnIIITtBuPP = meso‐tetrakis‐(4′‐tert‐butylphenyl)porphinatomanganese(III)] has been prepared and structurally and magnetically characterized. The uniform, linear‐chain (1‐D) coordination polymer comprises alternating cations and anions. The bond lengths in planar ion [C4(CN)6].‐]'‐ are 1.377(10) (CC–CC), 1.418(7) (C–CCC), 1.414 (C–CN), 1.457 (C–CNMn), 1.150 (CN), and 1.134 Å (C = NMn). The Mn–N–C angle is 172.3(4)°, and the intrachain Mn — Mn separation is 10.685 Å. Each [C4(CN)6].‐]' unit is bonded to two MnIII atoms through the interior nitrogen atoms in a trans‐μ2‐N‐σ manner with N–Mn bond lengths of 2.353 Å. The ṽCN absorptions are at 2217 (w, br) and 2190 (m) cm−1. Above 50 K the magnetic susceptibility of [MnIIITtBuPP]+[C4(CN)6].‐ can be fitted to the Curie‐Weiss expression, χ∝1(T – θ), with an effective θ of ‐13 K. This is consistent with weak antiferromagnetic coupling, which is in contrast to the effective θ of +67 K for the uniform chain [MnIIIOEP]+[C4(CN)6].‐ [OEP = octaethylporphinato]. Here, the [C4(CN)6].‐'‐ units are bonded to the MnIII centers through endo CN nitrogen atoms in a similar trans‐μ2 manner. Density functional theory MO calculations reveal that the spin density of the CN nitrogen atom bound to [MnIIITtBuPP]+ (0.019 μBÅ−3) is significantly lower than that of the N atom bound to [MnIIIOEP]+ (0.102 μBÅ−3). This is consistent with the reduced spin coupling observed for [MnIIITtBuPP]+[C4(CN)6].‐with respect to [MnIIITtBuPP]+[C4(CN)6].‐, as evidenced by the lower θ value. The different orientations of the [C4(CN)6].‐ units—almost perpendicular (84.72°) for [MnIIITtBuPP]+[C4(CN)6].‐ and substantially tilted (32.1°) for [MnIIIOEP]+ [C4(CN)6].‐ may also contribute to the poorer overlap and weaker spin coupling. Hence, binding between sites with large spin densities is needed to stabilize strong ferromagnetic coupling.
Design of Sequence‐Specific DNA‐Binding Ligands
Authors: Nielsen Peter E.
Published: July 2007

Double‐stranded DNA can be viewed as a multifunctional, modular receptor that can be read sequence‐selectively in a digital way (base pair per base pair) by a complementary, similarly modular ligand. This principle has been exploited in several approaches to design sequence‐specific DNA‐binding ligands, such as triplex‐forming oligonucleotides, peptide nucleic acids and minor groove binding polyamides.
Synthesis of (R)‐Sulforaphane Using [cpru(R, R)‐CHIRAPHOS)]+ as Chiral Auxiliary
Authors: Schenk Wolfdieter A. , Dürr Michael
Published: July 2007

A new enantioselective (80% ee) synthesis of (R)‐sulforaphane and its epimer (S)‐sulforaphane is described, which makes use of the pseudo‐tetrahedral complex fragment [CpRu‐(CHIRAPHOS)]+ as a chiral auxiliary. Reaction of the chloride complexes [CpRu(L–L)Cl] [L–L = 1,‐bis(diphenylphosphino)ethane (dppe), (2S,3S)‐and (2R,3R)‐bis(diphenylphosphino)‐butane ((S,S)‐ and (R, R)‐CHIRAPHOS, respectively)] with phthalimidobutyl methyl sulfide gives the thioether complexes [CpRu(L–L)(MeSC4H8NPhth)]PF6. Oxygen transfer from dimethyldioxirane (DMD) produces the corresponding sulfoxide complexes in high yield and high diastereoselectivity. Cleavage of the phthaloyl group with aqueous hydrazine and subsequent reaction with thiophosgene yields the sulforaphane complexes [CpRu(L–L)(MeS(O)C4H8NCS)]PF6. Treatment of these with sodium iodide finally liberates the sulforaphane without noticeable racemization.
Reiterative Synthesis of trans‐Fused Polytetrahydropyrans Using the Oxiranyl Anion
Authors: Mori Yuji
Published: July 2007

The oxiranyl anion is a very unstable nucleophilic epoxide. This previously uncommon nucleophile has now been used for the synthesis of polycyclic ethers. Alkylation of an oxiranyl anion, a three‐carbon building block, with a triflate derived from tetrahydropyran‐methanol followed by acid‐catalyzed 6‐endo cyclization provides a trans‐fused bicyclic compound. Reiterative application of this procedure enables the rapid construction of trans‐fused polytetrahydropyrans.
Synthesis of Glycodendrimers by Modification of Poly(propylene imine) Dendrimers
Authors: Ashton Peter R. , Boyd Sue E. , Brown Christopher L. , Nepogodiev Sergey A. , Meijer E. W. , Peerlings H. W. I. , Peerlings H. W. I. , Stoddart J. Fraser
Published: July 2007

The use of preformed poly‐(propylene imine) dendrimers (DAB‐dendr‐(NH2)x) for the rapid and facile construction of high molecular weight carbohydrate‐coated dendrimers (glyco‐dendrimers) is presented. An efficient attachment of spacer‐armed derivatives of D‐galactose and lactose to the primary amino end groups of DAB‐dendr‐(NH2)x has been achieved by means of amide bond formation, using the N‐hydroxysuccinimide coupling procedure. Acetate protecting groups have been employed in order to avoid side reactions at the coupling stage. Deacetylation leads to the target glycodendrimers. The reactivity of all the available DAB‐dendr‐(NH2)x (generations 1–5) has been investigated and a series of homologous carbohydrate‐coated dendrimers have been synthesized. In addition, the attachment of larger saccharide moieties has been demonstrated by the condensation of a trisgalactoside cluster with DAB‐dendr‐(NH2)x carrying both four and eight primary amino groups. The regularity of the glycodendrimers has been proven by NMR spectroscopy, and the molecular weights of the low‐generation carbohydrate‐coated dendrimers have been determined by mass spectrometry. Modifications of DAB‐dendr‐(NH2)x with biologically active carbohydrates affords a new and simple approach to high molecular weight compounds that may be considered as neoglycoconjugates with perfectly symmetrical structures and that offer much promise as multivalent ligands involved in carbohydrate‐protein interactions.
Synthetic Carbohydrate‐Containing Dendrimers
Authors: Jayaraman Narayanaswamy , Nepogodiev Sergey A. , Stoddart J. Fraser
Published: July 2007

Dendrimers coated with carbohydrates on their exterior surfaces have been constructed by using both convergent and divergent synthetic routes. Alternatively, cluster glycosides in the form of highly branched oligosaccharides can serve as dendritic wedges in the subsequent elaboration of fully carbohydrate dendrimers. It is anticipated that these novel saccharide‐containing polymers, which are highly branched and water‐soluble, will find applications of a biological nature as well as in the context of new materials.
The Phosphodiester Groups of d(TpT)− and d(TpG)‐ Coordinate to Platinum(II) in N,N‐Dimethylformamide
Authors: Kozelka Jiří , Barre Gilles
Published: July 2007

The propensity of the phospho‐diester group to bind platinum(II) was investigated by examining the reactions of the dinucleotide salts NH4{d(TpT)} and NH4{d(TpG)} with the complexes [Pt‐(NO3)(NH3)3]NO3 (1) and cis‐[Pt(NO3)2‐(NH3)2] (2) in N,N‐dimethylformamide. d(TpT)‐ coordinates to the platinum atom of both 1 and 2 through either of the two nonbridging phosphoryl oxygen atoms, as revealed by 31P NMR spectroscopy. Conversely, d(TpG)‐ binds to 1 through the guanine N7 atom. With 2, d(TpG)‐ forms monodentate adducts bound to N7(G), as well as two distinct macrochelates, in which N7(G) and one of the nonbridging phosphoryl oxygens are crosslinked by platinum. We suggest that guanine‐phosphoryl macrochelate complexes play a role as intermediates in rearrangements of platinum monoadducts formed with DNA.
Formal [4 + 3], [4 + 2], [4 + 1] cycloadditions and acid‐base reaction of 2‐methyl‐1,3‐dimorpholino‐1,3‐butadiene with Fischer carbene complexes
Authors: Barluenga José , Aznar Fernando , Fernández Mónica
Published: July 2007

2‐Methyl‐1,3‐dimorpholino‐1,3‐butadiene 1 reacted with α,β‐unsaturated Fischer carbene complexes to give a wide range of different products depending on the substitution pattern. Thus, sevenmembered rings (4, 5 and 6) could be obtained from chromium complexes 2 with aromatic or vinylic groups at the β position. Similar results were observed when α‐methyl‐substituted carbene complex 7 a was used. Six‐membered carbocycles (derivatives of cycloadducts 12 and 13) were isolated after reaction with both chromium and tungsten complexes bearing one or two alkyl groups at the β position (10 and 11). Moreover, cyclopentenones 20 were the main products when the starting carbene complexes were alkyl‐substituted at both α and β positions (19a, b) or when aromatic (19c, d) instead of vinylic complexes were used. A bicyclo[4.1.0]heptene system 18 has also been obtained in the special case of reaction with β,β‐dimethylvinylchromium complex 13b; its formation could be explained as a formal carbene insertion into a C–H bond. The behaviour of diene 1 towards alkoxymethylcarbene complexes 22 was unusual. The different reaction products (cyclopentadienes 23, bicyclo[3.1.0]hexenes 24, aromatic amine 25 and metallatrienes 26) imply a mechanism in which the deprotonation of the carbene complex by the diene is followed by Michael addition to the iminium salt formed.
Zinc(II)‐Catalyzed Disproportionation in Rubber: The mechanism of Sulfur Vulcanization Revisited
Authors: Nieuwenhuizen Peter J. , Timal Sandjai , Haasnoot Jaap G. , Spek Anthony L. , Reedijk Jan
Published: July 2007

Model studies have shown that cross‐link precursors, that is, intermediates in the sulfur vulcanization of rubber, are transformed into cross‐links by a nonsymmetric but regioselective disproportionation mechanism. Thus, two equivalents of the crosslink precursor of the type RSSX are transformed into XSX and the actual cross‐link RSSSR. Exchange of sulfur atoms is a prerequisite. A mechanism involving an SNi′ reaction with an allylic moiety, suggested in the literature, has not been observed. The disproportionation reaction is catalyzed by rubber‐soluble zinc‐dithiocarbamate complexes, an important class of vulcanization accelerators. By virtue of ligand‐functional‐group exchange reactions these complexes serve to transport and exchange sulfur atoms.
Controlling Self‐Assembly
Authors: Gillard Richard E. , Raymo FrançIsco M. , Stoddart J. Fraser
Published: July 2007

As a result of cooperative noncovalent bonding interactions (namely, π–π stacking, [CH…︁O] hydrogen bonding, and [CH…︁π] interactions) supramolecular complexes and mechanically interlocked molecular compounds—in particular pseudorotaxanes (precatenanes) and catenanes—self‐assemble spontaneously from appropriate complementary components under thermodynamic and kinetic control, respectively. The stereoelectronic information imprinted in the components is crucial in controlling the extent of the formation of the complexes and compounds in the first place; moreover, it has a very significant influence on the relative orientations and motions of the components. In other words, the noncovalent bonding interactions—that is, the driving forces responsible for the self‐assembly processes—live on inside the final superstructures and structures, governing both their thermodynamic and kinetic behavior in solution. In an unsymmetrical [2]catenane, for example, changing the constitutions of the aromatic rings or altering the nature of substituents attached to them can drive an equilibrium associated with translational isomerism in the direction of one of two or more possible isomers both in solution and in the solid state. Generally speaking, the slower the components in mechanically interlocked compounds like catenanes and rotaxanes move with respect to each other, the easier it is for them to self‐assemble.
Regulation of ACh receptor clustering by the tyrosine phosphatase Shp2
Authors: Zhao Xiaotao T. , Qian Yueping K. , Chan Ariel W.S. , Madhavan Raghavan , Peng H. Benjamin
Published: July 2007

At the vertebrate neuromuscular junction (NMJ), postsynaptic aggregation of muscle acetylcholine receptors (AChRs) depends on the activation of MuSK, a muscle‐specific tyrosine kinase that is stimulated by neural agrin and regulated by muscle‐intrinsic tyrosine kinases and phosphatases. We recently reported that Shp2, a tyrosine phosphatase containing src homology two domains, suppressed MuSK‐dependent AChR clustering in cultured myotubes, but how this effect of Shp2 is controlled has remained unclear. In this study, biochemical assays showed that agrin‐treatment of C2 mouse myotubes enhanced the tyrosine phosphorylation of signal regulatory protein α1 (SIRPα1), a known activator of Shp2, and promoted SIRPα1's interaction with Shp2. Moreover, in situ experiments revealed that treatment of myotubes with the Shp2‐selective inhibitor NSC‐87877 increased spontaneous and agrin‐induced AChR clustering, and that AChR clustering was also enhanced in myotubes ectopically expressing inactive (dominant‐negative) Shp2; in contrast, AChR clustering was reduced in myotubes expressing constitutively active Shp2. Significantly, expression of truncated (nonShp2‐binding) and full‐length (Shp2‐binding) forms of SIRPα1 in myotubes also increased and decreased AChR clustering, respectively, and coexpression of truncated SIRPα1 with active Shp2 and full‐length SIRPα1 with inactive Shp2 reversed the actions of the exogenous Shp2 proteins on AChR clustering. These results suggest that SIRPα1 is a novel downstream target of MuSK that activates Shp2, which, in turn, suppresses AChR clustering. We propose that an inhibitory loop involving both tyrosine kinases and phosphatases sets the level of agrin/MuSK signaling and constrains it spatially to help generate high‐density AChR clusters selectively at NMJs. © 2007 Wiley Periodicals, Inc. Develop Neurobiol, 2007
Reaktionen von Diaminen mit Fulleren C60
Authors: Kampe Klaus‐Dieter , Egger Norbert
Published: July 2007

Reactions of Diamines with Fullerene C60

Reactions of 1,2‐ and 1,3‐diamines 2a‐i, including diamines containing primary amino groups, with C60 (1) in toluene are described, leading to mono‐ and bisadducts 3–16. In this way fullerene derivatives carrying NH as a nucleophilic functional group have been synthesized. Yields and ratios of mono‐ and bisadducts formed depend on reaction conditions and on the structure of the diamine. The scope of this reaction leading to defined mono‐ and bisadducts in appreciable yields has been investigated. Mono‐ and bisadducts formed can be separated by column chromatography on SiO2. Mass and NMR spectra reveal that the isolated basic fullerene derivatives are dehydro adducts. NMR spectra show that the monoadducts have a symmetrical structure. In all cases investigated the addition forming the mono‐ and bisadducts of 1 occurs across a 6–6 bond. Likewise analogous additions take place with C70. Remarkably, tertiary diamines such as 2p and q react with 1 forming the monoadduct 8 in small yields by loss of an alkyl group. Proposed structures of some regioisomeric bisadducts are discussed.
Synthesis and conformational studies of pentahydroxy[2.1.2.1.1]‐ and hexahydroxy [2.1.1.1.1.1]metacyclophanes
Authors: Yamato Takehiko , Yasumatsu Masashi , Doamekpor Louis Korbla , Nagayama Souichiro
Published: July 2007

Base‐catalyzed condensation of 1,2‐bis[5‐tert‐butyl‐3‐(5‐tert‐butylsalicyl)‐2‐hydroxyphenyl]ethane (8) with formaldehyde in xylene affords a novel ethylene‐bridged calixarene‐analogous macrocyclic metacyclophane. However, not the desired 2 has been obtained. Instead, the novel macrocyclic compounds pentahydroxy[2.1.2.1.1]‐ (9) and hexahydroxy‐[2.1.1.1.1.1]metacyclophane (10) have been isolated in 35 and 25% yields, respectively. The mechanism for the above disproportionation occurring during the base‐catalyzed condensation of 8 to afford these macrocyclic metacyclophanes and their 1H‐NMR spectral behavior are discussed.
Deamination Reactions, 56. Cyclopropane Participation in Norbornyl Cations
Authors: Herrmann Roland , Kirmse Wolfgang
Published: July 2007

Nitrous acid deamination of spiro[bicyclo[2.2.1]heptane‐7,1′‐cyclopropan]‐endo‐2‐amine (13) affords 74% of the analogous endo alcohol 24‐OH and 26% of the rearranged exo alcohol 25‐OH. The exceptional preference for endo attack of the nucleophile is attributed to intervention of the bridged norpinyl cation 21 which is stabilized by the spiroannellated cyclopropane ring. The spiro[bicyclo[2.2.1]heptane‐3,1′‐cyclopropan]‐2‐yl cations 23 arising from Wagner‐Meerwein rearrangement are captured by water to give high exo:endo product ratios.
Synthesis and Solvolysis of Bicyclo[3.1.1]hept‐3‐en‐2‐yl, Bicyclo[3.1.1]hept‐2‐yl, and 2‐Halogenocyclohex‐2‐en‐1‐yl Methanesulfonates and p‐Nitrobenzoates
Authors: Bentley T. William , Norman Simon J. , Kemmer Ralf , Christl Manfred
Published: July 2007

As an extension of previous work bicyclo[3.1.1]hept‐3‐en‐2‐ol (5) was synthesised in four steps from benzvalene and is now much more accessible than by former routes. The 3‐bromo derivative 9 of 5 was obtained from bicyclo[2.1.1]hexene by addition of dibromocarbene and hydrolysis of the resulting dibromide 8. – Methanesulfonates were prepared from 5, 9, 2‐norpinanol (7) as well as from 2‐bromo‐ (11a) and 2‐chlorocyclohex‐2‐en‐1‐ol (11b). Due to its high reactivity, the bicycloheptenyl mesylate 12 could only be characterised by low‐temperature NMR spectra. At 20°C, 2‐norpinyl mesylate (16) rearranged slowly to endo‐ (endo‐17) and exo‐2‐norbornyl mesylate (exo‐17) in the ratio 2:1. The formation of endo‐17 was also the major process on treatment of 16 with aqueous ethanol or acetone. – Solvolyses of bicyclo[3.1.1]‐heptenyl mesylates 12 and 20 proceed 4–5 times more slowly than solvolyses of corresponding cyclohexenyl mesylates 21c and 21a. The β‐bromine substituent deactivates solvolyses of 21a compared with 21c, and 20 compared with 12, by a factor of 2 · 103. The allylic double bond accelerates solvolyses of 21c compared with cyclohexyl mesylate by a factor of 107. However, 12 solvolyses only 100 times faster than norpinyl mesylate 16, showing a 105‐fold effect due to cyclobutylcarbinyl ring expansion. From solvolysis data the energy difference between the 2‐norpinyl and 2‐norbornyl cation is estimated to be 16 kcal mol−1, in fair agreement with a recent ab initio calculation.
A Novel Cycloocta[d]‐/Barreleno[d]pyridazine Rearrangement
Authors: Baumann Luzian , Folkerts Andree , Imming Peter , Klindert Thilo , Massa Werner , Seitz Gunther , Wocadlo Sigrid
Published: July 2007

As part of the valence tautomeric system cyclooctatetraene (2) bicyclo[4.2.0]octa‐2,4,7‐triene (3), the monocyclic polyene (2) reacts as a dienophile with the diazadiene 3,6‐bis(trifluoromethyl)‐1,2,4,5‐tetrazine (1) to form after N2‐elimination two products: The 1 : 1‐adduct 6, a cycloocta[d]pyridazine, and the tetracyclic bis‐Diels‐Alder cycloadduct 9. Depending on solvent polarity and temperature, compound 6 displays interesting novel rearrangements. On refluxing in nonpolar solvents like toluene, compound 6 yields the barreleno[d]pyridazine 13 in high yield. Compound 13 can be oxidized with 4‐phenyltriazolinedione 14 to the barreleno[d]pyridazine 15. When the more polar nitromethane is used as a solvent, heating of 6 at 90° 2°C surprisingly leads to the dihydrocycloocta[d]pyridazine 18 in a multistep reaction including proton‐shift tautomerism and [1, 5]‐sigmatropic rearrangement. The structures of the compounds 15 and 18 were assigned by the spectral data and verified by X‐ray crystallography.
Crystal and molecular structure of newly synthesized 2,3,2′,3′‐Bis{8″,11″‐dioxa[4.3.3]propella(3″,4″)}biphenyl
Authors: Grochowski Jacek , Jamrozik Janusz , Serda Paweł , Zesławski Wojciech
Published: July 2007

The title compound 5 was obtained from 2,2′,3,3′‐tetramethylbiphenyl in a multi‐step reaction sequence leading to the bis(propellane). X‐ray structure analysis proved the identity of bis(propellane). In the solid state the molecule possesses roughly a twofold symmetry axis perpendicular to the biphenyl bond. The conformation of the molecule is determined by a 53.5(1)° torsional angle between the biphenyl planes. The propellane bond is parallel to the phenyl plane in both symmetric parts of the molecule, what implies a boat conformation of the fused six‐membered rings.
Substituent effects on the CC bond strength, 19. Geminal substituent effects, 10. Radical stabilization enthalpies of α,α‐bis(methoxycarbonyl)alkyl and tris(methoxycarbonyl)methyl radicals
Authors: Rakufs Klaus , Verevkin Sergey P. , Keller Manfred , Beckhaus Hans‐Dieter , Rüchardt Christoph
Published: July 2007

Heats of formation ΔH(g) were determined from enthalpies of combustion ΔH(c) and enthalpies of vaporization ΔH or enthalpies of sublimation ΔH for the eight substituted methanetricarboxylates 2a‐h. From these data and from previously determined enthalpies of formation Δ of substituted malonic esters new thermochemical group increments were derived. From these increments and from the recently published improved increments for carboxylic acid esters the gem. interaction enthalpies of two and three COOR groups were calculated. The radical stabilization enthalpies RSE of α,α‐bis(methoxycarbonyl)alkyl (18.2 kJ mol−1, 1a) and tris‐(methoxycarbonyl)methyl radicals (5.2 kJ mol−1, 1b) were derived from kinetic data obtained by means of our previously developed protocol. They were corrected for the gem. interaction energies of the ester groups in the ground state and are satisfactorily explained by an additive stabilizing effect of the ester substituents and by dipolar substituent interactions in the radicals. The dipolar energies were taken from MM2 calculations.
Photochemistry of a benzofuro‐annulated oxanorbornadiene formation of propellanes by trapping of an intermediate carbonyl ylide with CN and CC dipolarophiles
Authors: Bussenius Jörg , Keller Manfred , Eberbach Wolfgang
Published: July 2007

On photochemical excitation of the benzofuro‐annulated oxanorbornadiene 10 in the presence of dipolarophiles the 1:1 addition compounds 11, 22, 23a,b, and 24, respectively, are formed as the only monomeric products. The mechanistic interpretation is based on a reaction sequence which involves [2 + 2] photocycloaddition to the oxaquadricyclane 12, 1,3‐dipolar cycloreversion to the carbonyl ylide 13 and subsequent face‐selective trapping by the corresponding dipolarophile. No indication of the transformation of 13 to the highly strained [3]3,6‐oxepinophane 14 was obtained. With the formation of 11 one of the rare examples of the cycloaddition of a nitrile dipolarophile (i.e. acetonitrile) was uncovered.
Carbon–oxygen bond insertion in the reaction of dialkoxycarbenes with anhydrides
Authors: Pole David L. , Warkentin John
Published: July 2007

Dimethoxycarbene (1a) and methoxy(2,2,2‐trifluoroethoxy)‐carbene (1b) were generated in benzene solution by thermolysis of the corresponding 2,2‐dialkoxyoxadiazolines 7. The carbenes were trapped by intermolecular reaction with a variety of cyclic anhydrides 8. The products 9 are formally the result of carbene insertion into the bond between the carbonyl carbon and the ring oxygen atoms. The results of a competition between dimethylmaleic and dichloromaleic anhydrides for dimethoxycarbene suggests that this reaction proceeds by nucleophilic attack of dialkoxycarbene onto the carbonyl carbon atom of the anhydride.
Photoactive cyclophanes, I. Synthesis, photophysical and photochemical properties of cinnamophanes
Authors: Greiving Helmut , Hopf Henning , Jones Peter G. , Bubenitschek Peter , Desvergne Jean‐Pierre , Bouas‐Laurent Henri
Published: July 2007

In order to transfer the so‐called topochemical control established by Schmidt and coworkers to fluid solutions, the [2.2]paracyclophane framework was substituted with two acryloyl substituents, one on each of the two decks. The 4 products thus formed are termed cinnamophanes. The pseudo‐gem derivative, 1, was shown to undergo a very efficient stereospecific [2 + 2] photocycloaddition to form 5 with the highest quantum yield (0.8) ever observed for such a reaction. Whereas 2, 3 and 4, the regioisomers of 1, undergo a trans‐cis photoisomerisation, compound 1 leads to the photocycloadduct as the sole photoproduct. This unusually fast cycloaddition reaction is not sensitive to oxygen and is largely unaffected by temperature variations. It is believed to be a singlet state reaction. The synthesis and a spectroscopic (absorption and fluorescence emission) study of 1–4 and 5 are described.
Pheromone synthesis, CLXX. A new synthesis of faranal [(3S,4R,6E,10Z)‐3,4,7,11‐tetramethyl‐6,10‐tridecadienal], the trail pheromone of the pharaoh's ant, Monomorium pharaonis
Authors: Mori Kenji , Murata Noriaki
Published: July 2007

Faranal (1), the trail‐following pheromone of the worker of Pharaoh's ant (Monomorium pharaonis), was synthesized by the coupling reaction of the iododiene 3 with the chiral building block 8 as the key step. The geometrically pure iododiene 3 was prepared by the zirconocene‐mediated carboalumination reaction of 2 followed by treatment with iodine.
Theoretical Study of Pericyclic Reactions of Nitrosoethylene and (Thionitroso)ethylene
Authors: Sperling Dirk , Mehlhorn Achim , Reißig Hans‐Ulrich , Fabian Jürgen
Published: July 2007

Structure and reactivity of the title compounds 1 were examined by ab initio methods at the post Hartree‐Fock level of theory. Both compounds are expected to undergo electrocyclic ring closure to 4H‐1,2‐oxazete (4O) and 4H‐1,2‐thiazete (4S), respectively. The alternative electrocyclic reaction affording 2H‐azirine 1‐oxide (3O) and 2H‐azirine 1‐thioxide (3S) is definitely less favoured. (Thionitroso)ethylene (1S) is more reactive than the oxygen‐containing congener. The same holds for the cycloaddition reaction with ethylene. [4 + 2] Hetero Diels‐Alder reactions furnishing 4H‐1,2‐oxazine (5O) or 4H‐1,2‐thiazine (5S) are favoured over the [3 + 2] cycloaddition reactions providing 2H‐pyrrole 1‐oxide (2O) and 2H‐pyrrole 1‐thioxide (2S). The results of RMP2/6‐31G* calculations and results obtained at lower levels of theory (RHF, PM3) are compared and discussed with respect to the experimental material available. Some additional single‐point calculations at the computationally more demanding QC1SD/6‐31G* level confirmed conclusions drawn from RMP2 calculations. Some test calculations also showed that the theoretical results are less affected by consideration of the temperature by statistic thermodynamics and by inclusion of solvent effects by a self‐consistent reaction‐field method.
Sauerstoff‐Abfang von Radikalen in überkritischem Kohlendioxid; Bildungsenthalpie und Rekombinationsbarriere des Cycloheptatrienyl‐Radikals
Authors: Roth Wolfgang R. , Hunold Frank , Neumann Martin , Bauer Frank
Published: July 2007

Oxygen Trapping of Radicals in Supercritical Carbon Dioxide; Heat of Formation and Recombination Barrier of the Cycloheptatrienyl Radical

The homolytic thermal cleavage of bitropenyl (1) in supercritical carbon dioxide has been measured in the presence of 1 to 180 bar oxygen between 120 and 170°C. From these data the activation parameters of the dissociation and recombination reaction are derived, which lead to a heat of formation for the tropenyl radical (2) of ΔHfo = 64.7 kcal · mol−1. By using this value a radical stabilization energy (RSE) or 31.5 kcal · mol−1 is obtained, which differs by 1.7 kcal · mol−1 from the planar, acyclic isomer (trans,trans‐1,3,6‐trien‐5‐yl: RSE = 29.8 kcal · mol−1), which is practically equivalent to the relief of ring strain due to the formation of the radical. In agreement with the observed stability of 2 the equilibrium constant for its reaction with oxygen at 143°C is Keq = 727.7 mol−1, which corresponds to a bond strengths of 31.5 kcal ˙ mol−1 for R–O2·. The equipment and the method used for these experiments are described in detail.
Regioselectivity of Multiple Cyclopropanations of C60 and Introduction of a General Bond‐Labeling Algorithm for Fullerenes and Their Derivatives
Authors: Hirsch Andreas , Lamparth Irs , Schick Georg
Published: July 2007

A computational (AM1) analysis is presented which shows that the observed regioselectivities of multiple cyclopropanations of C60 are due to orbital‐allowed processes. Next to the coefficients of frontier orbitals the characteristic cage distortions of the oligomethanofullerenes are discussed. For further experimental corroboration the synthesis and characterization of an unsymmetrical trisadduct with a I, eI, III*‐addition pattern are described. Moreover, since a systematic and descriptive assignment of addition patterns in derivatives of C60 and higher fullerenes becomes more and more important, a simple and general algorithm is introduced, which enables unambiguous bond labeling of both [6,6]‐ and [5,6]‐bonds as well as the assignment of the absolute configuration of any fullerene derivative.
Supramolecular Chemistry, 62. Ligand and Cosubstrate Effects on the Hydrolysis of Phosphate Esters and DNA with Lanthanoids
Authors: Rammo Jörg , Schneider Hans‐Jörg
Published: July 2007

Attempts are described to enhance the catalytic activity of lanthanide ions by providing cosubstrates with an increasing number of nucleophilic groups or by attaching corresponding polyols covalently to stronger metal‐binding centers like diazacrown ethers. Although the kinetic effects on the hydrolysis of bis(4‐nitrophenyl) phosphate (BNPP) and of super‐coiled plasmid DNA are only moderate, their dependence on cosubstrate structure and polyol configuration unambiguously demonstrates that these are involved in the slow step of the reactions. Thus, addition of gluconic acid to a LaCl3solution leads to a marked increase of DNA cleavage from 20 to 71%. Naphthyl units covalently bound to the diazacrown show little effect onBNPPhydrolysis, but enhance DNA hydrolysis again from e.g. 38% (RF II) to 60%. Preliminary affinity measurements with calf thymus DNA, using a fluorimetric assay with ethidium bromide, show for polyamines a dependence on the number of ligand charges as observed earlier. The naphthyl compound is characterized by a high affinity; preliminary NMR data indicate that the naphthyl units intercalate into DNA.
Studies Related to Fatty Acid Desaturation, III. Preparation and Use of Thiaoleic Acids
Authors: Poulain S. , Noiret N. , Nugier‐Chauvin C. , Patin H.
Published: July 2007

New thiaoleic acid methyl esters 1 have been prepared as models for studies on Δ12‐saturation, Convergent synthetic pathways to those acids from the 10‐(tetrahydropyranyloxy)‐dec‐1‐yne 2 are described. After saponification, their inhibitory effect on the in vivo desaturation of [1‐14C] oleic acid into [1‐14C] linoleic acid has been evaluated using green algae, Chlorella sorokiniana, as a biological model. This result may indicate that the oleyl‐desaturase initiates dehydrogenation of a normal substrate by hydrogen atom abstraction at C‐13.
Pheromone Synthesis, CLXXV.– Synthesis of Koiganal I and II, the Sex Pheromone Components of the Webbing Clothes Moth
Authors: Takikawa Hirosato , Takenaka Motonobu , Mori Kenji
Published: July 2007

Koiganal I [(E)‐2‐octadecenal (1)] and II [(2E,13Z)‐2,13‐octadecadienal (2)], the female‐produced pheromone components of the webbing clothes moth (Tineola bisselliella), were synthesized.
Enantioselective Synthesis of (R)‐(+)‐Pulvilloric Acid
Authors: Rödel Thomas , Gerlach Hans
Published: July 2007

The fungal metabolite (R)‐(+)‐pulvilloric acid [(+)‐1] was synthesized for the first time. Reaction of the Grignard reagent of 5 with 2‐pentyloxirane (S)‐(−)‐4 in the presence of 1,5‐cyclooctadienecopper(I) chloride as the catalyst led to (S)‐(+)‐6. The enantiomer (S)‐(−)‐4 was prepared from dimethyl L‐malate via the dioxolane (S)‐(+)‐3. The alcohol (S)‐(+)‐6 was transformed into (R)‐(−)‐6 via the benzoate (R)‐(−)‐7 by a Mitsunobu reaction. Hydrogenolysis of (−)‐6 gave the resorcyl alcohol (R)‐(+)‐2. The remaining steps to produce (R)‐(+)‐1 from (+)‐2 required carboxylation to (R)‐(−)‐8, formylation and in situ ring closure with triethyl orthoformate to furnish the required quinomethide structure. Application of the same reactions to (S)‐(+)‐6 afforded (S)‐(−)‐1 via the intermediates (S)‐(−)‐2 and (S)‐(+)‐8. With (±)‐6 as starting material (±)‐2, (±)‐8 and (±)‐1 were prepared.
Side‐Chain Modifications of C60 via Activation of the Easily Accessible Fulleromalonic Acid C61(COOH)2
Authors: Lamparth Iris , Schick Georg , Hirsch Andreas
Published: July 2007

Side‐chain modifications of fullerenes can be achieved starting from the malonic acid 2, which is easily accessible by saponification of the corresponding diethyl malonate adduct 1 and is therefore an ideal building block for side chain chemistry on fullerenes. Coupling reactions are carried out via the synthesis of the fullerene active ester 4, which is formed by the reaction of the malonic acid 2 with N‐hydroxysuccinimide. During this reaction the malonic acid undergoes decarboxylation, yielding an acetic acid derivative instead of a malonic system. The active ester 4 is isolable and represents an ideal building block for fullerene chemistry. Sidechain modifications can also be carried out as one‐step reactions by preparing 4 in situ. We have performed coupling reactions with various compounds containing primary or secondary amino groups.
Rearrangements of 2‐ and 3‐Furfurylidene
Authors: Albers Reinhard , Sander Wolfram
Published: July 2007

The photo‐ and thermochemistry of diazo(2‐furyl)methane (3) and diazo(3‐furyl)methane (6) was investigated using the matrix isolation technique. Photolysis of 3 results in the formation of (Z)‐pent‐2‐en‐4‐yn‐1‐al (2) in a clean reaction, in agreement with the observation of Shechter et al. Photolysis or pyrolysis of diazo compound 6 yields (s‐Z)‐(α‐formyl)methylenecyclopropene (s‐Z‐13) as the only detectable product. Carbene 14 and cyclopropene 15 are proposed as intermediates, but not stable under the reaction conditions and thus not directly observed. The reaction sequence 6→13 provides a novel and simple route to methylenecyclopropenes.
The Photoaddition of Pyrroles to Arylethenes and Arylethynes
Authors: Austin Mark , Covell Christopher , Gilbert Andrew , Hendrickx Ramon
Published: July 2007

The photochemical reactions of styrene, (E)‐stilbene, phenyl‐ethyne, and diphenylethyne with pyrrole and N‐methylpyrrole have been investigated. The pyrroles quench the fluorescence of the phenylethenes and phenylethynes efficiently and broad structureless emissions attributed to exciplexes are observed from the N‐methylpyrrole systems. Substituted pyrroles (1:1 and 2:1 adducts) are formed from irradiation of the phenylethenes with pyrrole, and 2‐styrylpyrroles result from the phenylethynes. Styrene, but none of the other arenes, undergoes photoaddition to N‐methylpyrrole in the presence of 10% acetic acid.
Centrohexacyclic or “K5” Molecules: Development of a Growing Family of Topologically Nonplanar Organic Compounds
Authors: Kuck Dietmar
Published: July 2007

This article gives a comprehensive review of the synthetic development of centrohexacyclic organic compounds (“centrohexacyclanes”) during the past decade. With their unique feature of having a molecular constitution that corresponds to the complete graph K5, centrohexacyclanes represent the majority of the rare class of topologically nonplanar compounds. Starting from the few previously known organic, element–organic and inorganic K5 compounds, the syntheses of various organic centrohexacyclanes are discussed, based mainly on three different strategies that have emanated from the chemistry of centropolyindanes: the propellane, fenestrane, and “broken fenestrane” routes. In addition, the first results of some targeted transformations of centrohexaindane, the Td‐symmetrical hexabenzoannelated centrohexaquinane, are presented.
Stereoselective Synthesis of Alcohols, L. Synthesis and Conformational Studies of 1,5‐Dioxa‐cis‐decalin
Authors: Hoffmann Reinhard W. , Münster Ingo
Published: July 2007

cis‐2‐Vinyltetrahydropyran‐3‐ol (6) is accessible by a selective intramolecular allylboration reaction. Compound 6 was converted into 1,4‐dioxa‐cis‐decaline (4) and cis‐syn‐cis‐perhydrotrioxaanthracene 32; heterocycles with fused tetrahydropyran rings. These ring systems populate predominantly the conformation in which the oxygen atoms are in a gauche arrangement. The tricycle 31 is a rigid derivative of 14‐crown‐3 and, as in the case of 12‐crown‐3, it forms complexes with lithium ions in acetonitrile.
Recent Developments in the [1,2]‐Wittig Rearrangement
Authors: Tomooka Katsuhiko , Yamamoto Hiroshi , Nakai Takeshi
Published: July 2007

The stereochemical features and synthetic potentials of the [1,2]‐Wittig rearrangement are reviewed.
Selective CC Bond Cleavage of Quaternary β‐Amino Aldehydes and β‐Amino Ketones by Sodium–Amide‐Induced Grob‐Type Fragmentation
Authors: Mölm Detlef , Risch Nikolaus
Published: July 2007

Quaternary β‐amino aldehydes and β‐amino ketones are cleaved in a Grob‐type fragmentation induced by nucleophilic attack of NH2− on the carbonyl group of 3, to yield new carbonyl derivatives 4 and alkenes 5, and unsaturated amides 6, respectively.
Application of Vicarious Nucleophilic Substitution in Organic Synthesis
Authors: Ma̧kosza Mieczyslaw , Wojciechowski Krzysztof
Published: July 2007

Vicarious Nucleophilic Substitution (VNS) provides the possibility of the replacement of hydrogen atoms in electrophilic arenes with α‐functionalized alkyl substituents. This review focuses on the transformations of products obtained by VNS, particularly into heterocyclic compounds. In addition, some characteristic features of the VNS mechanism are briefly described.
Utilization of Industrial Waste Materials, 11. Synthesis of New, Chiral β‐sec‐Amino Alcohols – Diastereodivergent Addition of Grignard Reagents to α‐Amino Aldehydes Based on the (all‐R)‐2‐Azabicyclo[3.3.0]octane System
Authors: Wilken Jörg , Thorey Claire , Gröger Harald , Haase Detlev , Saak Wolfgang , Pohl Siegfried , Muzart Jacques , Martens Jürgen
Published: July 2007

New, chiral β‐sec‐amino alcohols (αR,βR)‐11a–13a, (αS,βR)‐11b–17b, (αS,βS)‐11c, 12c, 15c, 17c and (αR,βS)‐11d, 12d, 15d, 17d have been synthesized from the enantiomerically pure amine (all‐R)‐1a via diastereomeric, N‐tert‐butoxycarbonyl‐protected aldehydes 3. Grignard additions proceed in fair yields with a high degree of diastereofacial stereoselection (diastereomeric ratios dr up to ⩾ 95:5) with non‐chelation control, generally in favor of the anti‐(erythro) structures. A mechanistic interpretation of the stereochemical course of this reaction is presented. The stereodifferentiating ability of selected stereoisomeric (erythro)‐ and (threo)‐amino alcohol structures were tested in homogeneous catalysis, e.g. in two model reactions (optical purities up to 95%).
Cyclopropyl Building Blocks for Organic Synthesis, 42. An Unprecedented Mode of Ring Opening of Methylenecyclopropane Moieties – Reactions of Methylenecyclopropanecopper Reagents with an Electrophilic Glycine Equivalent
Authors: Kozhushkov Sergei I. , Brandl Melanie , Yufit Dmitrii S. , Machinek Reinhard , de Meijere Armin
Published: July 2007

The reactions of ethyl 2‐acetoxy‐2‐diphenylmethyleneaminoacetate (1) with organocopper reagents derived from bicyclopropylidene (2) and methylenecyclopropane (3) are accompanied by an unusual mode of opening of one three‐membered ring to give 4‐methylene‐1,2,3,4‐tetrahydropyridine derivatives 8a, 9 in good yields. The cuprate derived from methylenespiropentane (4) reacts with 1 to yield both the normal substitution product 14 (37%) as well as the rearrangement product 15 (34%), while the simple cyclopropylcuprate undergoes substitution to give the protected cyclopropylglycine 16 (75%) without rearrangement. The tetrahydropyridine 8a shows an interesting tautomerism in solution. The 4‐cyclopropylidenetetrahydropyridine 15 undergoes an unusual dehydrodimerization to produce two separable rotamers, C2‐19 and C1‐19, via 18.
Photoinduced Electron‐Transfer in Porphyrin‐quinone Cyclophanes, 15. Distance Dependence of Photoinduced Electron‐Transfer: Syntheses and Structures of Naphthalene‐Spacered Porphyrin‐Quinone Cyclophanes
Authors: Staab Heinz A. , Feurer Achim , Krieger Claus , Kumar A. Sampath
Published: July 2007

Syntheses, conformational and structural analyses of porphyrin‐quinone cyclophanes 2 with naphthalene‐spacers are presented and the findings are compared with data for previously investigated analogous benzene‐spacered compounds 1. In combination with data for the biphenylene‐ and anthracene‐spacered porphyrin‐quinone cyclophanes 3 and 4, to be published in following papers, the results reported herein allow some appraisal to be made of the distance dependences of photoinduced electron‐transfer from porphyrin to quinone units.
Some Reactions of the Chloromethyl trans‐β‐Styryl Sulfone Carbanion
Authors: Ma̧kosza Mieczyslaw , Krylova Irina
Published: July 2007

The chloromethyl trans‐β‐styryl sulfone carbanion reacts with benzaldehyde and acrylonitrile under phase‐transfer catalysis conditions to give 2‐phenyl‐3‐(trans‐β‐styrylsulfonyl)oxirane and bis(2‐cyanoethyl)chloromethyl trans‐β‐styryl sulfone, respectively, and with nitroarenes to form the products of vicarious nucleophilic substitution of hydrogen.
On the Oxidation of Bridged 1‐Naphthylamine and Aniline Derivatives – Formation of Substituted Quinoline and Benzo[c,d]indole Derivatives
Authors: Kanitz Andreas , Hartmann Horst
Published: July 2007

The bridged aniline or 1‐naphthylamine derivatives 8–10 react with nitrous acid in the presence of perchloric acid to give the bridged diphenoquinone diiminium salts 12·2 HClO4, 17·2 HClO4, 19·2 HClO4 and 23. The same products are obtained from these substrates upon their reaction with hydrogen peroxide. Upon treatment of the bridged diphenoquinone diiminium salts 12·2 HClO4 and 23 with base, a disproportionation reaction occurs resulting in the formation of the corresponding benzidine derivatives 13 and 26 and, following a multistep process, the quinoline derivatives 15 and 25 are obtained. Analogously, the 1,2‐dihydrobenzo[c,d]indole hydroperchlorate 10·HClO4 is transformed into the bridged benzidine derivative 21 and the bis(benzo[c,d]indol‐6‐yl) hydroperchlorate 20·HClO4. Furthermore, as a result of an oxidation process initiated by the protonated species of the corresponding indaminium salts, condensation of N,N‐dimethyl‐4‐nitrosoaniline (27) with the bridged aniline or naphthylamine derivatives 8a–8c leads to the N′‐(6‐quinolyl)‐substituted N,N‐dimethylbenzoquinone bis(iminium) salts 29a–28c rather than the corresponding indaminium salts 28a–28c.