The presence of the heterogeneous mesoporous Al-MCM-41 catalyst remarkably accelerated the cyanosilylation of various aldehydes and ketones with trialkylsilyl cyanide, giving the corresponding cyanohydrin silyl ethers in quantitative yields under mild reaction conditions.

t By application of t he cyanohydrin synthesis t o D-erythroso, D-arabinose-I-C14 a nd Dribose-I-C" have been prepared in overall radiochemical y ields of 30 and 8.5 pe rcent, respectively. General acid cat alys ts in t he cyanohydrin reaction appear to favor format ion of t he ambonic epimer. The epimeri c acids res ul t ing from t he reaction of labeled cyanide and D-ery throso, and subsequen...

Introduction: Both α-amino acids and α-hydroxy acids occur in aqueous extracts of the Murchison carbonaceous meteorite. The Strecker-cyanohydrin reaction, the reaction of carbonyl compounds, cyanide, and ammonia to produce amino and hydroxy acids, has been proposed as a source of such organic acids in meteorites [1]. Such syntheses are consistent with the suggestion [2] that interstellar precur...

The -ethylphenylamine tartaric acid salts 1a-1d were synthesized from R-(+)/S-(-)-ethylphenylamine by reacting with (2S,3S)-(+)/(2R,3R)-(-) dihydrobutanedioic acid. They were used as the catalysts in cyanosilylation of prochiral aldehydes to give the corresponding cyanohydrin trimethylsilyl ethers in moderate conversion at room temperature.

Hydroxynitrile lyases (HNLs) from Prunus amygdalus (PaHNL), Sorghum bicolor (SbHNL), Manihot esculenta (MeHNL) and Hevea brasiliensis (HbHNL) are excellent biocatalysts for the preparation of optically active cyanohydrins. (R)as well as (S)-cyanohydrins are obtained in high optical and chemical yields. The synthetic potential of the now easily available optically pure cyanohydrins is demonstrat...

The nature of the anionic ligand X (X = EtOSO3, BF4, Cl, Br, OSO2CF3, F or CN) in vanadium(V)salen complexes [V+ O(salen) X-] was found to have a significant influence on the catalytic activity of the complexes, but not on their enantioselectivities; with the complexes in which X = Cl or F being most active and the complex with X = OSO2CF3 being totally inactive.

The mechanism by which four Lewis bases, triethylamine, tetrabutylammonium thiocyanate, tetrabutylammonium azide and tetrabutylammonium cyanide, catalyse the addition of trimethylsilyl cyanide to aldehydes is studied by a combination of kinetic and spectroscopic methods. The reactions can exhibit first or second order kinetics corresponding to three different reaction mechanisms. Spectroscopic ...