bluuebunny/crossref_metadata_2025_split huggingface dataset:
Angular Distortions at Tetracoordinate Carbon Planoid Configurations in Substituted Spiro[4.4]nonanes
Authors: Luef Wolfgang , Keese Reinhart , Bürgi Hans‐Beat 
Published: December 2004

AbstractThe configuration of the spiro centre in polycyclic compounds containing a spiro[4.4]nonane substructure is analyzed in terms of symmetry coordinates. As revealed by X‐ray structures of such compounds, the local distortions around the quaternary C‐atom are dominated by a decrease of the ring‐bond angles at the spiro centre and a twist of one ring relative to the other. The planoid deformations given by the planarization index PC are comparatively small for spiro[4.4]nonanes, which contain either no additional bridges between the rings or only α,β′–or β,β′‐polymethylene bridges. This indicates that the local strain in the spiro C(C)4 fragments is rather small.
Syntheses of Diamino‐dideoxylyxose Derivatives using Acylnitroso Dienophiles
Authors: Defoin Albert , Fritz Hans , Schmidlin Christian , Streith Jacques 
Published: December 2004

AbstractN‐Acylnitroso derivatives 6 which were prepared by in‐situ oxidation of the corresponding hydroxamic acids 5 reacted instantaneously and in high yields with dihydropyridine 4. The Diels‐Alder adducts 8 were formed regiospecifically with the acylnitroso dienophiles 6a–c, whereas the dienophiles 6d–f gave mixtures of both regioisomers 7 and 8. These and some other results [2] were best explained by the FMO theory. The Diels‐Alder adducts 7 and 8 gave the corresponding ‘anti’‐cis‐glycols when reacted with OsO4/N‐methylmorpholine N‐oxide. Hydrogenolysis of the N–O bond followed by peracetylation led to the expected aminolyxose derivatives 14 and 16. A similar sequence, using 4 and the hydroxamic‐acid derivative 18 of (+)‐D‐mandelic acid led, with a poor asymmetric induction, to a mixture of the expected optically active aminolyxose compounds 19A/19B.
Potassium Carboxylates by Direct Carbonylation of Potassium Alkoxides
Authors: Rautenstrauch Valentin 
Published: December 2004

AbstractReaction of the K+ alkoxide of linalool (1) in benzene with CO at 425–440 bar and 120–130° for 12–30 h gave the K+ salt of 2,6‐dimethyl‐2‐vinyl‐5‐heptenoic acid (4a) in a ca. 25% yield based on ca. 65% converted alkoxide. Reaction of the [K+ ⊂ 18‐crown‐6] alkoxide of 1 with CO at 50–55 bar and 40° for 90–140 h gave a mixture containing mainly the [K+ ⊂ 18‐c‐6] salts of 4a (ca. 62%) and of the homogeranic acids 3a and 6a (together ca. 27% of the mixture) in a ca. 35% combined yield based on 50–60% converted alkoxide. The uncomplexed or complexed K+ alkoxide of (S)−1 gave, with ca. 85% net retention, the K+ salt of (S)‐4a. Reaction of the [K+ ⊂ 18‐c‐6] alkoxide of geraniol (2) with CO at 50 bar and 40° for 65–70 h gave myrcene (10) and geranyl formate (11) in a ca. 40–50% yield each based on ca. 85% converted alkoxide. Reaction of the [K+ ⊂ 18‐c‐6] alkoxide of 3‐pentyl‐1,4‐pentadien‐3‐ol (14) at 50 bar and r.t. for 70 h gave a mixture of the [K+ ⊂ 18‐c‐6] salts of 2‐pentyl‐2‐vinyl‐3‐butenoic acid (15a) (67%) and the 4‐pentyl‐2,4‐hexadienoic acids 18a and 19a (together 23% of the mixture) in a ca. 90% combined yield based on ca. 65% converted alkoxide.
Facile Hetero‐Diels‐Alder Reaction of α,β‐Unsaturated Acyl Cyanides and Enol Ethers: Syntheses of 2‐Alkoxy‐3,4‐dihydro‐2H‐Pyran‐6‐carbonitriles
Authors: John Robert A. , Schmid Vincent , Wyler Hugo 
Published: December 2004

Abstract2‐Ethoxy‐3,4‐dihydro‐2H‐pyran‐6‐carbonitriles are obtained in high yield by stereospecific endo‐mode cyclo‐additions of α,β‐unsaturated acyl cyanides and ethyl vinyl ether at room temperature. The nitrile group is converted to some other functionalities.
Coralloidin C, D, and E: Novel Eudesmane Sesquiterpenoids from the Mediterranean Alcyonacean Alcyonium coralloides
Authors: D'Ambrosio Michele , Guerriero Antonio , Pietra Francesco 
Published: December 2004

AbstractThe Mediterranean alcyonacean Alcyonium (=Parerythropodium) coralloides (Pallas, 1766) is shown to contain the novel eudesmane sesquiterpenoids coralloidin C (=(–)−(4R,10S)‐eudesma‐5,7(11)‐dien‐15‐yl acetate; (–)−4), coralloidin D (=(–)−(10R*)‐eudesma‐4,7(11)‐diene‐12,13‐diyl diacetate; (–)−7), and coralloidin E (=(+)−(4R*,10R*)‐eudesma‐5,7‐dien‐11‐ol;(+)−8). The absolute configuration of (–)−4 is derived by the exciton‐coupling method, applied to deacetylcoralloidin Cp‐anisate ((–)−6). Coralloidin E((+)−8), being also obtained on treatment of deacetylcoralloidin A (=(+)−(4R*, 8R*, 10R*)‐eudesma‐5,7(11)‐dien‐8‐ol; (+)−2) with (COCl)2 in DMSO, is configurationally correlated to coralloidin A (=(+)−(4R*, 8R*, 10R*)‐eudesma‐5,7(11)‐dien‐8‐yl acetate; (+)−1). Under acidic conditions, (+)−2 undergoes a complex rearrangement giving (+)‐(3R*, 4S*, 5R*, 6R*, 7S*)‐arist‐10‐(1)‐en ‐3‐ol ((+)−9), which is also obtained, together with (+)−8, on attempts to mesylate (+)−2.
Complete Sequence Determination and Localisation of One Imino and Three Sulfide Bridges of the Nonadecapeptide Ro 09–0198 by Homonuclear 2D‐NMR Spectroscopy. The DQF‐RELAYED‐NOESY‐Experiment
Authors: Kessler Horst , Steuernagel Stefan , Gillessen Dieter , Kamiyama Tsutomu 
Published: December 2004

AbstractThe constitution of the nonadecapeptide Ro 09–0198 (1) has been established by homonuclear two‐dimensional NMR spectroscopy. The peptide contains three sulfide bridges and a bridge formed from the side chain of a lysine residue (lysinoalanine moiety). Only the composition was known before, thus the complete sequencing and the elucidation of the bridges had to be performed. Of special importance was the application of the RELAYED‐NOESY experiment. This technique was improved by the introduction of a double‐quantum filter to reduce the tailing around the diagonal. The resulting sequence of 1 exhibits a surprizing analogy of this immunopotentiating peptide to the ACE inhibitor ancovenin.
Light‐Induced, Thermal, and Acid‐Catalyzed π‐Skeletal Rearrangements of Five‐Ring‐Annelated Heptalenes
Authors: Weber Roland H. , Brügger Paul , Jenny Titus A. , Hansen Hans‐Jürgen 
Published: December 2004

AbstractIt is shown that, upon irradiation in CDCl3 solution, 5,6,8,10‐tetramethylheptalene‐1,2‐dicarboxylic anhydride (6) rearranges to its double‐bond‐shift (DBS) isomer 7 in an equilibrium reaction (Scheme 2). The isomer 7 is DBS stable at −50°. At ca. 30°, a thermal equilibrium with 97.8% of 6 and 2.2% of 7 is rapidly established. Similarly, the ‘ortho’‐anhydrides 9 and 11 (Schemes 4 and 5) can be rearranged to their corresponding DBS isomers 12 and 13, respectively. Whereas 12 is DBS stable at 30° (at 100° in tetralin, 94.0% of 9 are in equilibrium with 6.0% of 12), the i‐Pr‐substituted isomer 13 is already at 30° in thermal equilibrium with 11 leading to 98.7% of 11 and 1.3% of 13. It is shown by rearrangement of diasteroisomeric ‘ortho’‐anhydrides of known relative and absolute configuration (Scheme 6) that the DBS in such five‐ring‐annelated heptalenes occurs with retention of the configuration of the heptalene skeleton as already established for other heptalene compounds. It is found that the DBS process may also take place under acid catalysis (e.g. HCl/CH3OH), thus yielding 9 from 12 (Scheme 9). The ‘ortho’‐anhydrides 21 and 23 (Scheme 10) which are isomeric with 9 and 11 (Scheme 3) undergo rapid DBS' already at room temperature. The thermal equilibrium 21⇄22 consists of 18% of 21 and 82% of 22 at 30° and that of 23⇄24 of 17% of 23 and 83% of 24 at −30°. From these equilibrium mixtures, the pure DBS isomer 22 can be obtained by crystallization. Again, these rapid DBS' occur with retention of configuration of the heptalene skeleton (Fig. 4).
Ringerweiterung durch Fragmentierung. Synthese von 15‐Pentadecanolid (Exaltolid®)
Authors: Milenkov Branimir , Guggisberg Armin , Hesse Manfred 
Published: December 2004

Ring Enlargement by Fragmentation. Synthesis of 15‐Pentadecanolide (Exaltolide®)The title compound was synthesized from 1‐(3′‐hydroxypropyl)‐2‐oxocyclododecane‐1‐carbonitrile (3), using two different routes (Scheme). The CN group of 3 was converted to the Me3N+ residue in 5 which underwent, upon NaH treatment, a fragmentation leading to the ring‐enlargement product 6. The same product was observed after heating the ring‐enlarged dimethylamine oxide 14, prepared from 3 by Bu4NF treatment and conversion of the CN into the dimethylamine‐oxide moiety. Ozonolysis of the methylidene double bond in 6 and reduction of the resulting C = O to a CH2 group gave Exaltolide® (8).
Verecynarmin A, a Novel Briarane Diterpenoid Isolated from Both the Mediterranean Nudibranch Molluse Armina maculata and its Prey, the Pennatulacean Octocoral Veretillum cynomorium
Authors: Guerriero Antonio , D'Ambrosio Michele , Pietra Francesco 
Published: December 2004

AbstractThe briarane diterpenoid verecynarmin A (=(−)).(8R,9S,11R,12aR,4Z,6Z)‐11,12‐epoxy‐8,8a,9,10,12,12a,13‐octahydro‐1,5,8a,12‐tetramethylbenzo[4,5]cyclodeca[1,2‐b]furan‐9‐yl acetate; ((−)‐1) is shown to be contained in both the Mediterranean nudibranch mollusc Armina maculata(RAFINESQUE) and its prey, the pennatulacean octocoral Veretillum cynomorium(PALLAS). The structure is mainly solved by 1D‐NMR, 2D‐NMR, and NOE studies of (−)‐1. However, the relative configurations at the epoxide and angular methyl centres, as well as the preferred conformation, are established by shift‐reagent and NOE studies of diol(−)‐4 obtained by epoxide‐ring opening of (−)‐1 with LiA1H4. The absolute configuration is established via deacetylation of (−)01 followed by Horeau's esterification.
2,4‐Bis(4‐methylpheylthio)‐1,3,2λ5,4λ5‐dithiadiphosphetan‐2,4‐dithion: Ein neues Reagens zur Schwefelung von N,N‐disubstituierten Amiden
Authors: Wipf Peter , Jenny Christjohannes , Heimgartner Heinz 
Published: December 2004

2,4‐Bis(4‐methylphenylthio)‐1,3,2λ5,4λ5‐dithiadiphosphetane‐2,4‐dithione: A New Reagent for Thiation of N,N‐Disubstituted AmidesAs a new reagent for the thiation of amides, the easily accessible 2,4‐bis(4‐methylphenylthio)‐1,3,2λ5,4λ5‐dithiadiphosphetane‐2,4‐dithione (9) shows a remarkable selectivity. This selectivity – the preferred thiation of N,N‐disubstituted amides – is complementary to the one of the well known Lawesson reagent. Thiation of diamides of type 2 with 9 leads via cyclization of the corresponding dithiodiamides to 1,3‐thiazole‐5(4H)‐thiones 1 (Scheme 3).
Sterospecific Syntheses and Spectroscopic Properties of Isomeric 2,4,6,8‐Undecatetraenes. New Hydrocarbons from the Marine Brown Alga Giffordia mitchellae. Part IV.
Authors: Boland Wilhelm , Schroer Nora , Sieler Christiane , Feigel Martin 
Published: December 2004

AbstractGiffordene (=(2Z,4Z,6E,8Z)‐2,4,6,8‐undecatetraene; 9f) and five steroisomers are new C11H16 hydrocarbons from the marine brown alga Giffordia mitchellae. Their synthesis is based on non‐stereoselective Wittig reactions of (E)‐2‐alkenals with appropriate acetylenic phosphoranes and subsequent chromatographic separation of the resulting (E/Z)‐pairs. The uniform enynes (>98% purity) are then stereospecifically reduced to (Z)‐alkenes with Zn(Cu/Ag) in aq. MeOH at r.t. 13C‐ and 1 H‐NMR data of the new tetraenes are presented. Biosynthetically, giffordene (9f) originates from dodeca‐3,6,9‐trienoic acid via an unstable (3Z,5Z,8Z)‐1,3,5,8,‐undecatetraene followed by a thermally allowed antarafacial 1,7‐sigmatropic hydrogen shift to the (2Z,4Z,6E,8Z)‐isomer9f.
Strukturaufklärung ungewöhnlicher Umlagerungsprodukte von S‐(1‐Alkenyl)sulfoximiden mit Hilfe der Stossaktivierungsmassenspektrometrie (CAD‐MS)
Authors: Veith Hans‐Jürgen , Gais Hans‐Joachim , Erdelmeier Irene 
Published: December 2004

Structure Determination of Unusual Rearrangement Products of S‐(1‐Alkenyl)sulfoximides by Collisionally Activated Dissoication Mass Spectrometry (CAD‐MS)The Molecular ions of s‐(l‐alkenyl)‐‐N‐(p‐tolyl)sulfoximides 1 are transformed into the N(phenylsufenyl)sulfonamides 3+ by a 1,2‐migration of the alkenyle group to the O‐atom of the sulfoximide function followed by a 2,3‐sigmatropic rearrangement. The structure of the production e has been unambiguouslydetermined by the CAD method, showing the identity of the ion e (m/z368) obtained from 1a and from 4a.
Raspailynes, Novel Long‐Chain Acetylenic Enol Ethers of Glycerol from the Marine Sponges Raspailia pumila and Raspailia ramosa
Authors: Guella Graziano , Mancini Ines , Pietra Francesco 
Published: December 2004

AbstractThe sponges Raspailia pumila and ramosa (Demospongiae, Tetractinomorpha, Axinellida) from the North‐East Atlantic are shown to contain a series of novel long‐chain enol ethers of glycerol where the enol ether CC bond is conjugated, in sequence, to both an acetylenic and an olefinic bond. Polar extracts give raspailynes hydroxylated at their (1Z5Z)‐1,5‐alkadien‐3‐ynyl chain, like raspailyne Al ( = (+)‐(S)‐3‐[((1Z,5Z)‐16‐hydroxy‐hexadeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; (+2) and isoraspailyne A ( = (+)‐3‐[((1Z,5Z)‐17‐hydroxyocta‐deca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐[propanediol; (+)‐3). Less polar extracts give 3 different types of raspailynes not hydroxylated at the chain. Raspailynes of the first type have either the (1Z,5Z)‐configuration in a linear chain such as raspailyne B2 (( = (−)‐(s)‐3‐[((1Z,5Z)‐trideca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; (−)‐4), raspailyne Bl ( = (−)‐3‐[((1Z,5Z)‐tetradeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol;(−)‐5), and raspailyne B ( = 3‐[((1Z,5Z)‐pentadeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; 6) or the (1Z,5Z)‐pentadeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; 6)or the (1Z,5Z)‐configuration in a chain ending with an isopropyl group, like isoraspailyne Bl ( = 3‐[((1Z,5Z)‐12‐methyltrideca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; 7) and isoraspailyne B ( = 3‐[((1Z,5Z)‐13‐methyltetradeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; 8). Raspailynes of the second type have the (1Z,5E)‐configuration, like isoraspailyne Bla ( =3‐[((1Z,5E)‐tetradeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; 9) and isoraspailyne Ba ( = 3‐[((1Z,5E)‐13‐methyltetradeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol; 10). Raspailynes of the third type have the (1E,5Z)‐configuration, like isoraspailyne Blb ( = 3‐[((1E,5Z)‐tetradeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2,‐propanediol; 11). The (S)‐configuration for (+)‐1,((+)‐2, and (−)‐4 is derived from chemical correlations.
Complexes of 2,2′,2″‐Nirtilotriphenol. Part IV. Cage Compounds with Phosphorus(III) and Phosphorus(V)
Authors: Müller Edgar , Bürgi Hans Beat 
Published: December 2004

AbstractThe ligand 2,2′,2″‐nitrilotriphenol reacts with P(III) and P(V) compounds to form corresponding phosphorus complexes. Syntheses and NMR data of 2,2′,2″‐nitrilotriphenyl phosphite (II), 2,2′,2″‐nitrilotriphenyl phosphate (III) and of a hydrolysis product of II, 2,2′‐[N‐(2‐hydroxyphenyl)imino]diphenly phosphonate (IV), are reported, as well as crystal structures of II and IV. Phosphite II shows a bicycloundecane framework; no NċPinteraction is present. The phosphonate IV shows two coordinated and one dangling phenol group; the N‐atom does not interact with the P‐atom. Strong acids protonate II as well as III to form cations: in these, NMR evidence indicates coordination of the N‐atom to the P‐atom.
Oxidative Breaking of Long‐Chain Acetylenic Enol Ethers of Glycerol of the Marine Sponges Raspailia pumila and of Model Compounds with Aerial Oxygen
Authors: Guella Graziano , Mancini Ines , Pietra Francesco 
Published: December 2004

AbstractThe raspailynes (novel long‐chain enol ethers of glycerol having the enol ethers double bond conjugated in sequence, to an acetylenic and an olefinic bond, isolated from the North‐East‐Atlantic sponges Raspailia pumila and R. ramosa) are stable under normal hydrolytic conditions for enol ethers. In contrast, when their solutions are evaporated, these lipids such as raspailyne Bl (=(−))‐3‐[(1Z,5Z)‐(tetradeca‐1,5‐dien‐3‐ynyl)oxy]‐1,2‐propanediol;(−‐2) rapidly react with aerial O2 under normal laboratory‐daylight conditions, with rupture of the C=C enol ether bond to give 1‐O‐formylglycerol (3) and an aldehyde (such as tridec‐4‐en‐2ynal(4) from (−)‐2). This reaction must be caused by triplet O2, since thermally generated singlet O2 has no effect on (−)‐2 in solution. That the mere presence of an enol‐ether moiety conjugated to an acetylenic group is responsible for such a behaviour is demonstrated with the model compounds 1‐methoxypentadec‐1‐en‐3‐yn‐5‐ol (6a) and its 5‐O‐acetyl or 5‐O‐tetra‐hydropyranyl derivatives 6b and 6c, respectively. Resistance to both hydroytic conditions and singlet O2 of these compounds is thought to arise from electron depletion at the enol‐ether C(beta;) atom by the acetylenic group. Plausible reaction pathways for enol‐ether bond rupture in these compounds by aerial O2 are outlined.
β‐Cleavage of Bis(homoallylic) Potassium Alkoxides. Preparation of 3‐Hydroxypropyl and 4‐Hydroxybutyl Propenyl Ketones from γ‐ and δ‐Lactones. Synthesis of (±)‐Rose oxide
Authors: Snowden Roger L. , Linder Simon M. , Muller Bernard L. , Schulte‐Elte Karl H. 
Published: December 2004

AbstractStarting from γ‐ and δ‐lactones 1–3, a two‐step preparation of 3‐hydroxypropyl and 4‐ hydroxybutyl propenyl ketones 10–18 is described, involving as the key step the β‐cleavage of the bis(homoallylic) potassium alkoxides 4a–9a. The novel methodology is illustrated by a short synthesis of (±)‐rose oxide(20).
A Torquospecific 1,5‐Electrocyclization
Authors: Gesche Paul , Klinger François , Riesen Andreas , Tschamber Théophile , Zehnder Margareta , Streith Jacques 
Published: December 2004

AbstractSaponification of homodiazepine 1a and 1b, in the absence of any proton donors, led to the formation of the 6π electron anionic species A which, by virtue of a 1,5‐electrocyclization, is in equilibrium with the allylic anion B. This latter tricyclic species is thermodynamically less favoured than its bicyclic isomer A. Nevertheless, B could be trapped by acylation and led tupe‐2 compounds which are the major reaction products. This is due to the fact that B is more nucleophilic and, therefore, much more reactive than A. The transoid topology of the tricyclic products 2 was demonstrated by 1H‐NMR and by an X‐ray diagram of 2d. The transoid geometry of 2 is a consequence of a torquospecific 1,5‐electrocyclization (of A), which is due to a steric, and possibly even to an electronic factor.
Pulse Radiolytic Studies of 1‐Halo‐2‐(methylthio)ethanes in Hexane and 1,2‐Dichloroethane: Formation of an Intermolecular Species with a Three‐Electron Bond between Sulfur and Iodine
Authors: Anklam Elke , Mohan Hari , Asmus Klaus‐Dieter 
Published: December 2004

Abstract1‐Iodo‐2‐(methylthio)ethane was synthesized via a ring‐opening reaction of thiirane with MeI in MeCN. The S‐centered radical cation of this compound undergoes an intermolecular stabilization with the I substituent of a second unattacked substrate molecule to yield an magnified image bonded radical cation. The oxidation was initiated by solvent radical cations in irradiated 1,2‐dicloroethane and hexane solutions. The 2ρ/ρ* three‐electron‐bonded species exhibits an optical absorption band at 410 nm, detectable by pulse radiolysis. During its decay, a new, longer‐lived absorption band is formed at 380 nm which is assigned to . The latter is suggested to result from anchimeric assistance in the generation of a cyclic sulfonium salt. The radical cations of 1‐bromo‐and 1‐chloro‐2‐(methylthio)ethane are assumed to undergo raped cyclization to the sulfonium salt without stabilization in any intermolecular S‐Br or S‐Cl interaction.
Azomalonic Ester Syntheses. Part I. One‐Step Synthesis of Triazolo[1,4]benzodiazepines from Azomalonates. Preparation of Novel Polyaza Tricycles from Diethyl (2‐Chloroacetamido)malonate
Authors: Heckendorn Roland 
Published: December 2004

AbstractA useful synthetic principle for the preparation of N‐heterocycles consists in the base treatment of azoma‐lonates carrying electrophilic centers in the side chain. Thus, pharmacologically active triazolo[1,4]benzodiazepine‐carboxamides can be prepared in one step from azomalonates derived from 2‐aminobenzophenones and diethyl (2‐chloroacetamido)malonate. The same malonate coupled with diazotized 3‐amino‐2‐chloropyridine leads in 2 steps to 3 novel pyridotriazoloazines. Similarly, N‐protected 2‐amino‐diphenylamine derivatives are converted into triazoloquinoxaline‐carboxylic acids. The heteocycles are further characterized by functional‐group inter‐conversion. Some mechanistic aspects of the azomalonic‐ester synthesis are discussed.
Asymmetric Induction at C(β) and C(α) of N‐Enoylsultams by Organomagnesium 1,4‐Addition/Enolate Trapping
Authors: Oppolzer Wolfgang , Poli Giovanni , Kingma Arend J. , Starkemann Christian , Bernardinelli Gérald 
Published: December 2004

AbstractThe 1,4‐addition of alkylmagnesium chlorides to conjugated N‐enoylsultams and subsequent ‘enolate trapping’ with aq. NH4Cl or MeI/hexamethylphosphoric triamide generated centers of asymmetry at C(β) and/or at C(α) with good to excellent π‐face defferentiation as demonstrated by the conversions 1→2, 1→4, and 8→9. This holds also for the regioselective 1,4‐addition of EtMgC1 to a dienoylsultam (15→16). Reactive conformations 1≠, 8≠, 13, and 14 are postulated in agreement with X‐ray evidence which also served for the structure determination of the product 9j.
Aminierende reduktive Kupplung aromatischer Aldehyde mit niervalenten Titan‐Reagenzien zu 1,2‐Diarylethylendiaminen
Authors: Betschart Claudia , Seebach Dieter 
Published: December 2004

Preparation of 1,2‐Diarylethylenediamines by Aminative Reductive Coupling of Aromatic Aldehydes with Low‐Valent Titanium ReagentsIn a novel McMurry‐ Type one‐pot reaction, aromatic aldehydes and secondary amines are poupled of give the N, N, N′, N′‐tetraalkyl‐1,2‐diarylethylendiamines 1–22 (Table 3). To this end, a lithium dialkylamide is added to an aromatic aldehyde to give the adduct B which is then treated with 1 equiv. of TiC14 to yield a coloured suspension of a reagent synthetically equivalent to a iminium salt (C/D in Scheme 4). After treatment with a low‐valent Ti reagent which is prepared by reduction of TiC14 with either K or, preferably, Mg, the coupling products are isolated in 23 to 81% yield as a 1:1 mixture of the diastereoisomers (meso‐ and rac‐form). These are separated either by chromatography or by crystallization and characterized.
Synthesis and Reactions of Optically Active 1,3‐Diols
Authors: Rösslein Lukas , Tamm Christoph 
Published: December 2004

AbstractThe ‘syn’‐1,3‐diols 3,4 and 5 with a C7, C6, and C5 chain, respectively, were synthesized from methyl hydrogen 3‐hydroxyglutarate (2; Schemes 1 and 2). The latter is available in (R)‐ and (S)‐configuration. Octyl (3R)‐4‐chloro‐3‐hydroxybutanoate (17) is an alternative starting material for the preparation of 5 (Scheme 3.) The epoxide 20, derived from 5 in a one‐pot reaction, is a versatile synthon, which selectively reacts with a great number of nucleophiles (Scheme 4).
Dendryphiellin A, the First Fungal Trinor‐eremophilane. Isolation from the marine deuteromycete Dendryphiella salina (SUTHERLAND) PUGHet NICOT
Authors: Guerriero Antonio , D'Ambrosio Michele , Pietra Francesco , Cuomo Vincenzo , Vanzanella Fortunato 
Published: December 2004

AbstractThe novel metabolite dendryphiellin A ( = (+)‐(1R,2S,8aR)‐ 1,2,6,7,8,8a‐hexahydro‐7‐hydroxy‐1,8a‐dimethyl‐6‐oxonaphthalen‐2‐yl (6R*, 2E,4E)‐8‐hydroxy‐6‐methylocta‐2,4‐dienoate; (+)‐1) is isolated from cultures of the marine deuteromycete Dendryphiella salina. There is no precedent in fungi for trinor‐eremophilanes or for branched C9 carboxylic acids, the two classes of compounds constituting (+)‐1. The structure is secured by NMR spectroscopy and hydrolysis of (+)‐1 to give the side‐chain moiety ((6R*,2E,4E)‐8‐hydroxy‐6‐methylocta‐2,4‐dienoic acid (2)) intact, whilst the trinor‐ermophilane moiety is decomposed. The absolute configuration at the trinor‐eremophilane moiety is established from exciton coupling between the dienone and the diene‐ester functions.