Design of Chiral Phase Transfer Catalyst with Conformationally Fixed Biphenyl Core: Application to Asymmetric Alkylation of Glycine Derivatives
作者:Yong-Gang Wang、Keiji Maruoka
DOI:10.1021/op0602324
日期:2007.5.1
Chiral phase transfer catalysts (S)-1a and (S)-1b with a conformationally fixed biphenyl core were conveniently prepared from the known (S)- 6,6')-dimethylbiphenyl- 2,2')- diol 2 in five steps. These catalysts, (S)-1a and ( S)-1b, are readily applicable to asymmetric alkylation of glycine derivatives with excellent enantioselectivity. In particular, catalyst (S)-1b was found to exhibit a unique temperature effect on the enantioselectivity, and asymmetric alkylation of glycine derivatives at room temperature gave a higher ee than that at 0 degrees C.
US8110680B2
申请人:——
公开号:US8110680B2
公开(公告)日:2012-02-07
US8252952B2
申请人:——
公开号:US8252952B2
公开(公告)日:2012-08-28
US8263798B2
申请人:——
公开号:US8263798B2
公开(公告)日:2012-09-11
Convenient preparation of chiral phase-transfer catalysts with conformationally fixed biphenyl core for catalytic asymmetric synthesis of α-alkyl- and α,α-dialkyl-α-amino acids: application to the short asymmetric synthesis of BIRT-377
Chiral phase-transfer catalysts (S)-1a, (S)-1b, and (S)-2 with conformationally fixed biphenyl cores were conveniently prepared from the known, easily available (S)-6,6′-dimethylbiphenyl-2,2′-diol 3 and (S)-4,5,6,4′,5′,6′-hexamethoxybiphenyl-2,2′-dicarboxylic acid 14, respectively, in five steps. The catalysts, (S)-1a and (S)-1b are readily applicable to asymmetric alkylation of N-(diphenylmethylene)glycine