Catalytic, asymmetric Strecker reactions catalysed by titaniumIV and vanadiumV(salen) complexes
摘要:
Vanadium(V)(salen) complex 3 has been found to be an effective catalyst for the asymmetric addition of hydrogen cyanide (generated in situ from trimethylsilyl cyanide) to imines. The best results (up to 81% enantiomeric excess) were obtained for aromatic imines in which the nitrogen atom is protected with a benzyl group and in which the imine bond is not sterically encumbered. (c) 2006 Elsevier Ltd. All rights reserved.
[EN] PROCESS FOR THE CYANATION OF IMINES<br/>[FR] PROCEDE DE CYANATION D'IMINES
申请人:NPIL PHARMACEUTICALS UK LTD
公开号:WO2007093764A1
公开(公告)日:2007-08-23
[EN] The present invention relates to a process for the cyanation of imines, particularly to the asymmetric cyanation of imines. The Strecker reaction consists of a reaction between an aldehyde and an amine to form an imine, followed by the conversion of the imine to an alpha-amino nitrile by asymmetric catalysis. The present invention relates to a series of vanadium catalysts which allow the reduction of the imine in the Strecker reaction to be performed in good conversion and also with good ee values. The chiral catalysts are of formula (1a) or (1b). [FR] La présente invention concerne un procédé de cyanation d'imines, notamment de cyanation asymétrique d'imines. La réaction de Strecker consiste en une réaction entre un aldéhyde et une amine pour former une imine, suivie de la conversion de l'imine en un nitrile alpha-aminé par catalyse asymétrique. La présente invention concerne une série de catalyseurs à base de vanadium permettant de réaliser la réduction de l'imine dans la réaction de Strecker avec une bonne conversion et de bonnes valeurs d'ee. Les catalyseurs chiraux sont représentés par la formule (1a) ou (1b) :
Highly Enantioselective Titanium-Catalyzed Cyanation of Imines at Room Temperature
作者:Abdul Majeed Seayad、Balamurugan Ramalingam、Kazuhiko Yoshinaga、Takushi Nagata、Christina L. L. Chai
DOI:10.1021/ol902540h
日期:2010.1.15
A highly active and enantioselective titanium-catalyzed cyanation of imines at roomtemperature is described. The catalyst used is a partially hydrolyzed titanium alkoxide (PHTA) precatalyst together with a readily available N-salicyl-β-aminoalcohol ligand. Up to 98% ee was obtained with quantitative yields in 15 min of reaction time using 5 mol % of the catalyst. Various N-protecting groups such as
Catalytic, asymmetric Strecker reactions catalysed by titaniumIV and vanadiumV(salen) complexes
作者:John Blacker、Lisa A. Clutterbuck、Michael R. Crampton、Christophe Grosjean、Michael North
DOI:10.1016/j.tetasy.2006.05.015
日期:2006.5
Vanadium(V)(salen) complex 3 has been found to be an effective catalyst for the asymmetric addition of hydrogen cyanide (generated in situ from trimethylsilyl cyanide) to imines. The best results (up to 81% enantiomeric excess) were obtained for aromatic imines in which the nitrogen atom is protected with a benzyl group and in which the imine bond is not sterically encumbered. (c) 2006 Elsevier Ltd. All rights reserved.