The enantioselective addition of trimethylsilyl cyanide to a variety of aldehydes proceeded by the aid of a catalyst prepared in situ from titanium tetraisopropoxide [Ti(O-i-Pr)4] and chiral Schiff bases and gave the corresponding cyanohydrins in high optical yield (up to 96% e.e.). A remarkable rate enhancement was brought about by the addition of the Schiffbase to the titanium alkoxide mediated
A variety of aldehydes (aromatic, heteroaromatic, alpha,beta-unsaturated, and nonconjugate aliphatic aldehydes) has been trimethylsilylcyanated in highly enantiomeric excess (ee) with a catalyst prepared in situ from titanium tetraisopropoxide [Ti(O-i-Pr)4] and chiral Schiff bases. A remarkable rate enhancement was brought about by the addition of the Schiff base into the titanium alkoxide mediated silylcyanation of aldehydes. The chemical structure of chiral Schiff base-titanium alkoxide complexes is discussed based on their C-13 NMR spectra, field desorption (FD) mass spectra, and molecular weights.
PmHNL catalyzed synthesis of (R)-cyanohydrins derived from aliphatic aldehydes
作者:Samik Nanda、Yasuo Kato、Yasuhisa Asano
DOI:10.1016/j.tetasy.2006.02.003
日期:2006.3
Hydroxynitrile lyase from the Japanese apricot (Prunus mume) catalyzes the formation of several aliphatic cyanohydrins in an asymmetric fashion. By employing a biphasic reaction system, aliphatic aldehydes with various structural features can be converted to the corresponding (R)-cyanohydrins with good overall yield and enantiomeric excess. (c) 2006 Elsevier Ltd. All rights reserved.
Warmerdam; Van Den Nieuwendijk; Kruse, Recueil des Travaux Chimiques des Pays-Bas, 1996, vol. 115, # 1, p. 20 - 24
作者:Warmerdam、Van Den Nieuwendijk、Kruse、Brussee、Van Der Gen
DOI:——
日期:——
Masahiko Hayashi, Tetsuya Inoue, Yasunori Miyamoto, Nobuki Oguni, Tetrahedron, 50 (1994) N 15, S 4385-4398