The enantioselectiveStreckerreaction of N-diphenylphosphinoyl ketoimines has been achieved by use of in situ prepared chiral N,N‘-dioxide catalyst from l-piperidinamide 3f and m-chloroperoxybenzoic acid (m-CPBA). Excellent yields (up to 99%) and high enantioselectivities (up to 92% ee) were obtained. In particular, in situ prepared catalyst with readily available chiral material made the procedure
Enantioselective Strecker-type reaction of phosphinoyl ketimines catalyzed by a chiral Zr-bipyridyldiol catalyst
作者:Yi-Jing Chen、Chinpiao Chen
DOI:10.1016/j.tetasy.2008.09.011
日期:2008.9
An enantioselective Strecker reaction of N-diphenylphosphinoyl ketimines with TMSCN employing a chiral zirconium complex formed from chiral bipyridyl diol 1 as catalyst is described. The catalytic efficiency of chiral ligand 1 with other Lewis acids was also explored. Higher yields (50-85%) with moderate to good enantioselectivities (30-80%) were achieved for a variety of N-diphenylphosphinoyl ketimines. (C) 2008 Elsevier Ltd. All rights reserved.
General and practical catalytic enantioselective Strecker reaction of ketoimines: significant improvement through catalyst tuning by protic additives
Significant improvement in enantioselectivity and catalyst activity was achieved for the catalytic enantio selective Strecker reaction. Using a catalyst (1-2.5 mol%) prepared from Gd((OPr)-Pr-i)(3) and D-glucose derived ligand 1, and in the presence of 2,6-dimethylphenol as an additive, high enantioselectivity was obtained from a wide range of ketoimines, including heteroaromatic and cyclic ketoimines. The new method was applied to an efficient catalytic asymmetric synthesis of sorbinil, a therapeutic agent for diabetic complications. (C) 2004 Elsevier Ltd. All rights reserved.