Enantioselective synthesis of α-hydroxy phosphonates using the LaLi3tris(binaphthoxide) catalyst (LLB), prepared by an improved method
作者:Hiroaki Sasai、Masahiro Bougauchi、Takayoshi Arai、Masakatsu Shibasaki
DOI:10.1016/s0040-4039(97)00437-1
日期:1997.4
LaLi3tris(binaphthoxide) catalyst (LLB), which is prepared from LaCl3·7H2O (1 mol equiv), (R)- or (S)-BINOL dilithium salt (2.7 mol equiv), and NaO-t-Bu (0.3 mol equiv), is effective for the hydrophosphonylation of various aldehydes to give desired α-hydroxyphosphonates in up to 95% ee (88% yield). It is also noteworthy that with slow addition of the aldehydes the enantiomeric excesses of the products
LALI 3三(binaphthoxide)催化剂(LLB),它是从制备的LaCl 3 ·7H 2 O(1摩尔当量),(- [R )-或(小号)-BINOL二锂盐(2.7摩尔当量)和NaO-吨- Bu(0.3摩尔当量)可有效用于各种醛的氢膦酰化反应,以高达95%ee(88%收率)的方式提供所需的α-羟基膦酸酯。还值得注意的是,随着醛的缓慢添加,产物的对映体过量增加。