bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemistry of sulfonyl cyanides. Part 4: Diels‐alder cycloadditions of sulfonyl cyanides with dienes
Authors: Jagt J. C. , van Leusen A. M. 
Published: September 2010

AbstractTosyl cyanide reacts under extremely mild conditions with 2,3‐dimethyl‐1,3‐butadiene, isoprene and, under somewhat different conditions, with 1,3‐butadiene. The products, 2‐tosylpyridines and 3,6‐dihydro‐2‐pyridones, are derived by dehydrogenation and hydrolysis, respectively, of the Diels‐Alder cyclo‐adducts formed in situ. Phenylmethanesulfonyl cyanide and 1‐adamantane‐sulfonyl cyanide give analogous results with 2,3‐dimethylbutadiene.At 175°C, tosyl cyanide and tetracyclone form 3,4,5,6‐tetraphenyl‐2‐tosylpyridine. Phenylmethanesulfonyl cyanide and p‐chlorobenzenesulfonyl cyanide react similarly.
Chemistry of acetylenic ethers 103 Stereospecific addition of Grignard compounds to 1‐alkynyl sulfides in the presence of copper(I) halide
Authors: Vermeer P. , de Graaf C. , Meijer J. 
Published: September 2010

AbstractExcellent yields of vinylic sulfides R1R2CCHS‐CH3are produced in acis‐addition reaction, from 1‐alkynyl sulfides R1CCS‐CH3and Grignard compounds R2MgX under the influence of copper(I) halide in tetrahydrofuran.
Folded conformations. Part VI. An NMR spectroscopic study of the preferred solution conformation of N,N′‐[bis(α‐tosylbenzyl)]urea
Authors: Tel R. M. , Engberts Jan B. F. N. 
Published: September 2010

AbstractComparison of NMR spectral data of a number of N‐tosylalkyl‐ and N,N′‐bis(tosylalkyl)ureas reveals that the methyl protons of the tosyl moiety and the α‐sulfonyl alkyl proton in the N,N′‐[bis(α‐tosylbenzyl)]ureas 1‐3 resonate at unusually high fields. The presence of both sulfonyl groups and the aromatic rings of the benzyl moieties are prerequisites for the observation of appreciable upfield shifts. Evidence is presented that intramolecular shielding phenomena are involved. It is proposed that 1‐3 in solution predominantly adopt conformations in which each tosyl methyl group is positioned in the shielding region of the phenyl ring of the most remote benzyl group.
Electrochemical hydrocoupling of 2‐alkanones with ethyl acrylate and acrylonitrile
Authors: Fröling A. 
Published: September 2010

Abstract4‐Methyl‐4‐alkanolides can be prepared by electrochemical hydrocoupling of 2‐alkanones with ethyl acrylate. Good yields are obtained up to 2‐heptanone; 2‐octanone gives moderate yields, whereas 2‐undecanone does not couple at all, indicating the limit of this method. Information on the course of these coupling reactions, including the optimum electrode potential, was obtained from cyclic voltammetric investigations.
The crystal structure and absolute configuration of the 3‐p‐iodobenzoate‐11‐acetate of secogorgosterol
Authors: Enwall E. L. , van der Helm Dick 
Published: September 2010

AbstractThe crystal and molecular structure of a cyclopropane containing marine steroid, secogorgosterol and its absolute configuration have been determined by single X‐ray diffraction studies on the 3‐p‐iodobenzoate‐11‐acetate derivative. The compound crystallizes in space group PI with reduced cell dimensions a = 9.58, b = 16.38, c = 9.80, α = 96.71, β = 139.75, γ = 94.29. There is one formula unit (C39H55O5I) per unit cell (Z = I). Crystal data were obtained on a G.E. XRD‐5 diffractometer using the moving‐crystal, moving‐counter method, and the structure refined by least squares methods to a conventional R of 6.7% on all (2409) data. The structure determination confirms the presence of a cyclopropane ring in the side chain of the gorgosterol system while a trans conformation is observed about the 22‐23 bond.
Selective halogenation using molecular sieves
Authors: van Dijk J. , van Daalen J. J. , Paerels G. B. 
Published: September 2010

AbstractOn treatment of aromatic compounds, entirely adsorbed in type X molecular sieves, with bromine or chlorine a selective halogenation is found to take place. Alkylbenzenes give mainly ‐ and halogenobenzenes almost exclusively ‐ the para isomers. The bromination of alkylbenzenes takes place only in the ring. Phenyl ethers undergo a strong deactivation of the aromatic ring.In halogenations of toluene and halogenobenzenes, the use of catalytic amounts of CaX in which in most cases part of the cation is exchanged by Fe+++, result also in a significantly higher para/ortho ratio, than in reactions homogeneously catalyzed by FeCl3.
Alkyl α‐bromoalkanecarbodithioates Preparation and reaction with some nucleophilic reagents
Authors: Wesdorp J. C. , Meijer J. , Vermeer P. , Bos H. J. T. , Brandsma L. , Arens J. F. 
Published: September 2010

AbstractDithiocarboxylic esters, R1R2CHCSSCH3 (R1 and R2 = H or CH3), can be converted into α‐bromodithio esters, R1R2C(Br)CSSCH3, by reaction with the complex of bromine and dioxane. The results of a preliminary study of the type of reaction between (CH3)2C(Br)CSSCH3 and some nucleophilic reagents are reported.
Hydrogenolysis of 2,4,6‐tris(aryloxy)‐s‐triazines over palladium: A new method for the replacement of phenolic hydroxyl groups by hydrogen
Authors: van Muijlwijk A. W. , Kieboom A. P. G. , van Bekkum H. 
Published: September 2010

AbstractHydrogenolysis of a series 2,4,6‐tris(aryloxy)‐s‐triazines (obtained from cyanuric chloride and the corresponding phenols) over palladium on carbon gave the corresponding arenes in excellent yields.The rate of hydrogenolysis is not influenced by the electronic character of the substituents; increase in the size of the substituents retards the reaction.Both base and catalyst support were found to promote the reaction and their role in the hydrogenolysis reaction has been studied.
13CMR analysis of methyl octadecenoates
Authors: Bus J. , Frost D. J. 
Published: September 2010

AbstractCarbon‐13 magnetic resonance spectra have been measured of methyl cis‐ and trans‐octadecenoates with the double bond positions 8, 9, 10, 11 and 12.The chemical shift of the allylic carbon atoms displays a large dependence on the stereochemistry of the double bond: δ ≈︁ 27.3 ppm for the cis and δ ≈︁ 32.6 for the trans configuration. The difference in chemical shift between the two ethylenic carbon absorptions increases significantly as the double bond approaches the ester group. Thus, the position as well as the configuration of the double bond in methyl 8‐ up to 12‐octadecenoates can readily be established by 13CMR.
Ring transformations in reactions of heterocyclic compounds with nucleophiles (IX). Conversion of N‐methylpyrimidinium salts in pyridines by carbanions
Authors: Oostveen E. A. , van der Plas H. C. 
Published: September 2010

AbstractOn treatment with active methylene compounds in basic media the quaternary pyrimidinium salts, i.e. methyl l‐methylpyrimidinium sulfate, 1‐methyl‐4‐phenylpyrimidinium iodide and 1‐methyl‐5‐phenylpyrimidinium iodide are converted into pyridine derivatives. The mechanism of the reaction is discussed.
Studies on organophosphorus compounds ‐ VII. Synthesis of phenolic esters of N,N‐dimethylphosphoramidic acids and N,N‐dimethylphosphoramidochloridic acid from hexamethylphosphoric triamide
Authors: Perregaard J. , Pedersen E. B. , Lawesson S.‐O. 
Published: September 2010

AbstractHeating hexamethylphosphoric triamide (HMPA) with phenols at about 230° for 20‐30 hours yields a mixture of mono‐ and di‐substituted esters of phosphoramidic acidsP(O)(NMe2)n‐(Oψ3‐n n = 1,2 and in some cases rather high yields of triesters of phosphoric acid are isolated. The distribution of products varies with the structure of the phenols and the relative amount of HMPA. Some phenols do not give the expected phosphoramidic acids, but the corresponding N,N‐dimethylanilines.In the presence of HCl phenols react with an excess of HMPA to give fairly good yields of phenolic esters of N,N‐dimethylphosphoramidochloridic acid, P(O)(Cl)(NMe2)(Oψ).
Synthesis and reactions of 3,5‐dichloro‐4H‐1,2,6‐thiadiazin‐4‐one
Authors: Geevers J. , Trompen W. P. 
Published: September 2010

AbstractTreatment of 3,4,4,5‐tetrachloro‐4H‐1,2,6‐thiadiazine (1) with formic acid affords the title compound 2 in high yield. Replacement reactions of 2 with various N‐, O‐and S‐nucleophiles are described. The structure of the thiadiazine ring in the compounds prepared is discussed.
Ring transformations in reactions of heterocyclic halogeno compounds with nucleophiles (XXXVIII). The influence of leaving group mobility on reactions of 4‐X‐6‐methyl (or phenyl)‐pyrimidine 1‐oxides with liquid ammonia and with potassium amide in liquid ammonia
Authors: Peereboom R. , van der Plas H. C. 
Published: September 2010

AbstractThe influence of leaving group character on ring contraction and amination in reactions of 4‐X‐6‐R‐pyrimidine 1‐oxides [X=Cl, Br, I, SC6H5, OC6H5, N⊕ (CH3)3, and RCH3 or C6H5] with liquid ammonia at − 33°C and with potassium amide in liquid ammonia at − 75°C has been investigated. The rate of C(4) addition decreases in the series N⊕(CH3)3 > Cl, Br, I > OC6H5, SC6H5, being qualitatively in accordance with the leaving group mobility order. The influence of leaving group activity on the ring contraction followed the reverse order.
The chemistry of small ring compounds. Part 25. 1‐Acetoxycyclopropanol, a convenient precursor for cyclopropanone
Authors: van Tilborg W. J. M. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractThe acetoxy group in 1‐acetoxycyclopropanol can be replaced easily by various nucleo‐philes (e.g. CN, N3, NR2, OR, SR). Such reactions proceed via cyclopropanone, which is present together with acetic acid, in a small equilibrium concentration. It is shown that the use of 1‐acetoxycyclopropanol as a practical source of highly reactive cyclopropanone has many advantages over that of the latter.The ability of 1‐acetoxycyclopropanol to give cyclopropanone, ‐ in contrast to many other 1‐substituted cyclopropanols ‐, is due to the strong intramolecular hydrogen bridge between the hydroxyl and the acetyl group, as shown by infrared and NMR studies.
The chemistry of small ring compounds. Part 26. The chemistry of 1‐(dimethylamino)cyclopropanol
Authors: van Tilborg W. J. M. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractThe hydroxyl group of the title compound can easily be displaced by all common nucleophiles. The mechanism of such displacements is discussed in terms of an SN1 type reaction involving the cyclopropaniminium ion as an intermediate. An explanation is given why weak acids are good catalysts for such displacements, while mineral acids are poor.The reaction of 1‐(dimethylamino)cyclopropanol with ketene and isocyanates leads to the formation of transient cyclopropanone. Ketene and isocyanates do not react simply with the hydroxyl group of 1‐(dimethylamino)cyclopropanol, but form derivatives of dimethylamine besides the liberated cyclopropanone.
The reaction of chlorodithioformates with Grignard reagents
Authors: Larsson F.C.V. , Lawesson S.‐O. 
Published: September 2010

AbstractEthyl and phenyl chlorodithioformate have been reacted at −20°C with phenylmagnesium bromide and p‐tolylmagnesium bromide to give substituted thioketones 4 in acceptable yields. The reaction between methyl chlorodithioformate and methylmagnesium iodide at −40°C gave dimethyl trithiocarbonate and 3,3,7,7‐tetrakis(methylthio)‐1,2,4,6‐tetrathiepane‐5‐thione (8). When the reaction took place at 0°C other compounds also were isolated in small yields.
A synthesis ofcis‐6‐alken‐4‐olides
Authors: Russell S. W. 
Published: September 2010

Abstractcis‐6‐Alken‐4‐olides have been prepared by coupling the Iotsich complex of 1‐alkynes with epichlorohydrin to give chlorohydrins which are dehydrochlorinated to 1,2‐epoxy‐4‐alkynes. Condensation of these with sodium diethyl malonate in dimethylformamide gives the (ethoxycarbonyl)acetylenic lactones which are saponified and decarboxylated to give 6‐alkyn‐4‐olides. Reduction with hydrogen over Lindlar's catalyst furnishes the title compounds.
The manganese(III) acetate initiated synthesis of carboxylic acids from α‐olefins and acid anhydrides
Authors: de Klein W. J. 
Published: September 2010

AbstractUnder appropriate conditions manganese(III) acetate can be used as a free radical initiator to effect the addition of acid anhydrides to α‐olefins in a chain reaction. This results in an efficient synthesis of straight chain or α‐branched carboxylic acids. In this reaction manganese(III) acetate compares favourable with known peroxidic initiators. A mechanistic scheme accounting for the observed products is proposed.
The chemistry of small ring compounds. Part 30. Reactions of arylcyclopropanone hemiacetals with bases and acids
Authors: Bakker B.H. , van Ramesdonk H.J. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractThe arylcyclopropanone methyl hemiacetals (aryl = C6H5, p‐ClC6H4 and p‐CH3C6H4) are quantitatively isomerised by sodium methoxide or tert‐amines to propionic esters. The ring fission is rapid and occurs exclusively at the C1‐C2 position, leading to products derived from the most stable incipient carbanion.The hemiacetals react with acids via a Woodward‐Hoffmann cleavage of the C1‐C3 cyclopropyl bond, affording a mixture of 1‐ and 3‐substituted arylacetones, the ratio of which depends on the nature of the acid. This acid‐catalysed C2‐C3 ring‐fission only occurs when an aryl group is present. The unsubstituted cyclopropanone hemiacetal isomerises in (weak) acid to the propionic ester (C1‐C2 rupture).The transformation of arylcyclopropanone methyl hemiacetals in acidified methanol to α‐aryl‐α‐methoxy‐acetones, is first order in the hemiacetal. From the rate constants a Hammett ρ value of −0.7 is obtained, thus showing a small interaction of the aryl group with the remote reaction centre. This is considered to support a mechanism in which arylcyclopropanone is an essential intermediate. Subsequent protonation of this ketone with simultaneous C2‐C3 bond rupture gives the substituted 2‐hydroxyallylic cation. For this step an approximate ρ value of −2.9 is calculated, thus indicating that this step is much more sensitive to the presence of a (para) substituent in the aromatic ring. Further evidence for the occurrence of an intermediate arylcyclopropanone is the alkoxy exchange in the starting material when CD3OD or n‐propanol is used as solvent. The proposed mechanism is also consistent with the observed stability of the corresponding arylcyclopropanone acetals under similar acidic conditions.
Conformation of non‐aromatic ring compounds −91. Carbon‐13 nuclear magnetic resonance spectra of some mono‐ and di‐alkyl substituted glutaric anhydrides
Authors: Koer F.J. , de Hoog A.J. , Altona C. 
Published: September 2010

AbstractFourier transform carbon‐13 nuclear magnetic resonance spectra of glutaric anhydride and ten of its derivatives have been obtained and interpreted. The effects of alkyl substituents on the carbon shieldings of the glutaric anhydride skeleton are compared with similar effects obtained for alkylcyclohexanes and cyclohexanones. Some additivity parameters have been derived and are used to estimate the conformational equilibrium composition of 2‐methylglutaric anhydride. 3‐Alkyl substituted glutaric anhydrides display unusual high field chemical shifts of the carbon at the 3‐position.
Photochemical hydroxylation of 7,8‐dimethylalloxazine (lumichrome)
Authors: Duren R.R. , Dekker R.H. , Verbeek J. 
Published: September 2010

AbstractAnaerobic irradiation of an aqueous acid solution of lumichrome (7,8‐dimethylalloxazine) initially leads to the formation of 9‐hydroxylumichrome (II), 5,10‐dihydrolumichrome (III) and 9‐hydroxy‐5,10‐dihydrolumichrome (IV) in equilibrium with lumichrome (I). Prolonged irradiation results in complete conversion of lumichrome into 9‐hydroxy‐5,10‐dihydrolumichrome (IV). The composition of the irradiated solutions has been analyzed from spectral data.
Model experiments on the construction of the ABE ring system of hetisine type diterpene alkaloids
Authors: van Der Baan J.L. , Bickelhaupt F. 
Published: September 2010

AbstractThe cyanopyridinediols 5 were C‐alkylated to the unsaturated six‐membered imides 6. The allyl derivatives 6c and 6d underwent Cope rearrangement to 8a and 8b, respectively. The latter was transformed to the bromohydrin 9a which, after protection of the hydroxyl group, was cyclized by base to 11a. Removal of the protecting group and oxidation afforded ketone 12, a simple model compound containing the ABE ring system of hetisine type diterpene alkaloids. Its synthesis appears suitable for extensions including the CD ring system.
Copper(II)‐catalyzed formation of decenoic acids from manganese(III) acetate and 1‐octene in acetic anhydride/acetic acid mixtures
Authors: de Klein W. J. 
Published: September 2010

AbstractThe reaction of 1‐octene with manganese(III) acetate in acetic anhydride/acetic acid mixtures in the presence of Cu(II) salts gives 4‐decenoic acid as a major product, together with some 3‐decenoic acid. The 4‐decenoic acid, after esterification, is shown to consist mainly of the trans‐isomer, some cis‐isomer being also present.4‐Acetoxydecanoic acid, γ‐hexyl‐γ‐butyrolactone and decanoic acid are minor side products. A reaction mechanism is proposed.
Kinetics of the vinyl acetate synthesis from acetylene and acetic acid with a zinc acetate catalyst
Authors: Cornelissen A. E. , Valstar J. M. , van den Berg P. J. , Janssen F. J. 
Published: September 2010

AbstractDifferential and integral kinetic measurements were performed in order to estimate a reaction rate expression for the synthesis of vinyl acetate from acetylene and acetic acid. Zinc acetate on activated carbon was used as catalyst.magnified imageThe adsorption constant K3 has been calculated from integral reactor data.Literature adsorption data together with rate data at not too low values of pHOAc could satisfactorily be explained by assuming that the C2H2 adsorption is the rate controlling step. At high conversions and low partial pressures of acetic acid the acetic acid‐adsorption becomes the rate controlling step and the mechanism changes.In the rate expression k = k∞ exp(‐E/RT), with k∞ = 5.08 * 103 kmol·kg cat−1·sec−1·atm−1 E = 20.3 * 103 kcal·kmol−1 and K1 = exp(3.8 * 103/T − 8.6 atm−1). K3 = exp(‐8.4 * 103/T + 20.4 atm−1) for the molar feed ratio acetylene: acetic acid = 4.0 and K3 = 2.6 atm−1 for the ratio 1.5.
Chemistry of acetylenic ethers 110 a convenient synthesis of 1‐alkynyl ethynyl sulfides preparation of mono‐substituted 1,4‐dithiins, 1,4‐thiaselenins and 1,4‐thiatellurins
Authors: Zilverschoon A. , Meijer J. , Vermeer P. , Brandsma L. 
Published: September 2010

Abstract1‐Alkynyl ethynyl sulfides RC≡CS‐C≡CH (2) are easily accessible starting from 1‐alkynyl trimethylsilylethynyl sulfides RC≡CS‐C≡CSi(CH3)3(1).When compounds2are treated with sodium sulfide, selenide or telluride in methanol 1,4‐dithiins, 1,4‐thiaselenins and 1,4‐thiatellurins are obtained in good yields.
Chemistry of electron‐rich conjugated polyenes (II)Synthesis of 1,1‐dimethoxy‐ and 1,1,4‐trialkoxy‐1,3‐butadienes and of 1,1,6,6‐tetramethoxy‐1,3,5‐hexatriene
Authors: Scheeren J. W. , Marcelis A. T. M. , Aben R. W. , Nivard R. J. F. 
Published: September 2010

AbstractSeveral poly‐unsaturated, conjugated ketene acetals (Table I) have been obtained by 1,2‐ or 1,4‐elimination of alcohol with potassium amide from unsaturated acetals or ortho‐esters having hydrogen in an allylic position. The products have properties similar to simple electron‐rich olefins as is apparent from their smooth addition reactions with alcohols.
The reactions between 1′,3′,3′‐trimethylspiro[2H‐1‐benzopyran‐2,2′‐indolines] and 1,1‐bis[4‐(dimethylamino)phenyl] ethylene; products and mechanism
Authors: Zwanenburg D.J. , Maas Th. A. M. M. 
Published: September 2010

AbstractThe reaction between 1′,3′,3′‐trimethylspiro[2H‐1‐benzopyran‐2,2′‐indoline] and its derivatives (3a‐e) and 1,1‐bis[4‐(dimethylamino)phenyl]ethylene (“Michler's ethylene”) (4) were studied. Depending on the reaction time, the isomeric products 2,2‐bis[4‐(dimethylamino)phenyl]‐4‐{2‐methylidene‐1,3,3‐trimethylindoline}chromans (7a‐e) or 1′,3′,3′‐trimethyl‐4‐{2,2‐bis[4‐(dimethyl‐amino)phenyl]vinyl}‐spiro[chroman‐2,2′‐indolines] (8a‐d) were obtained. With deuterium labelled “Michler's ethylene” and deuterated solvents the mechanism of this reaction was confirmed. Reaction of the 2,2‐bis[4‐(dimethylamino)phenyl]‐2H‐chromenes 10c,d and 1,3,3‐trimethyl‐2‐methylene‐indoline (9) furnished the dihydrospiropyrans 8c,d. Chromene 10c and 1,1‐bis(p‐methoxyphenyl)‐ethylene gave 2.2‐bis(4‐methoxyphenyl)‐4‐ [2,2‐bis[4‐(dimethylamino)phenyl]vinyl}chroman. No fast proton exchange was observed in any of the reactions we have studied.
Catalyse acide intramoléculaire dans l'hydrolyse des acétals I. Position du proton dans l'état de transition
Authors: Buffet C. , Lamaty G. 
Published: September 2010

AbstractThe hydrolysis of a series of carboxy and methoxycarbonyl acetals, (Ib ‐ IXb and Ia ‐ IXa) derived from substituted salicylic acids and benzaldehydes has been studied. A strong intramolecular acid catalysis has been observed in the hydrolysis of substituted carboxy acetals.The values of the Hammett ρ coefficients measuring the influence of substituents located in the aldehyde and phenol moieties are respectively −2.95 and + 0.93.Comparison with the ρ values obtained with methoxycarbonyl acetals indicates that the C–O bond is largely broken in the transition state. The Bronsted α coefficient for carboxy‐group catalysis is quite small, ∼0.2 ± 0.1, suggesting a low degree of proton transfer in the transition state.
A convenient synthesis of codeine and morphine
Authors: Beyerman H. C. , Lie T. S. , Maat L. , Bosman H. H. , Buurman E. , Bijsterveld E. J. M. , Sinnige H. J. M. 
Published: September 2010

AbstractAcid‐catalysed cyclization of 1‐(3,5‐dihydroxy‐4‐methoxybenzyl)‐N‐formyl‐1,2,3,4,5,8‐hexahydro‐6‐methoxyisoquinoline (2c), where the benzyl group is symmetrically substituted, gave N‐formyl‐2‐hydroxynordihydrothebainone (4c) exclusively. The 2‐hydroxyl substituent could be removed selectively in high yield, via the 1‐phenyltetrazol‐5‐yl ether (4d), to yield N‐formylnordihydrothebainone (4e). (‐)‐N‐Formylnordihydrothebainone (4e) was reduced to (‐)‐dihydrothebainone (4a). The conversion of 4a to codeine (1b) and morphine (1a) has already been recorded.
The chemistry of small ring compounds. Part 31 Thermolysis of some substituted (o‐hydroxyphenyl)cyclopropanes
Authors: van der Vecht J. R. , Spoor R. M. , Steinberg H. , de Boer Th. J. 
Published: September 2010

AbstractCyclopropanes 1b, 1c and 1d, carrying an o‐hydroxyphenyl group as a proton donor and ‐ at the same small ring carbon atom ‐ a potential proton acceptor X = NMe2, OMe or SMe, have been thermolysed. Between 350° and 600° cyclopropyl‐ring opening takes place with isomerization to substituted (o‐hydroxyphenyl)propenes 8b, 8c and (mainly) 8d, each of which can be hydrolysed to o‐hydroxypropiophenone 2. Only when X = SMe, does protonation on sulfur lead to formal MeSH elimination. A similar reaction is also found when X = Me3N⊕, thus sharply contrasting with X = Me2NH⊕.
Stereospecific addition of organocopper(I) reagents to 1‐alkynylphosphines. A new example of α‐hetero‐substituted vinylcopper(I) compounds
Authors: Meijer J. , Westmijze H. , Vermeer P. 
Published: September 2010

AbstractHomocuprates R2CuMgX and heterocuprates [RCuBr]MgX can be reacted easily with 1‐alkynylphosphines R′‐C≡C‐P(C6H5)2 (R′ = H or CH3), leading exclusively to vinylic phosphines RR′CCHP(C6H5)2 after protonation, in almost quantitative yields. The additions proved to be stereospecific, only cis‐additions were observed as was shown by 1H‐NMR and GLC.
The crystal and molecular structure of dicyclopropylethanedione, C8H10O2
Authors: Lute C.N.A. , Statu C.H. 
Published: September 2010

AbstractDicyclopropylethanedione forms monoclinic crystals with cell constants: a = 6.317, b = 9.990, c = 6.078 Å and β = 90.34°. The space group is P21/n and there are two molecules in the unit cell. The molecules in the crystal are centrosymmetric with the CO groups trans with respect to each other. Each CO is cis relative to the adjacent cyclopropane ring (bisected conformation).