Enantioselective synthesis of quaternary stereogenic centers through catalytic asymmetric addition of dimethylzinc to α-ketoesters with chiral cis-cyclopropane-based amide alcohol as ligand
作者:Bing Zheng、Shicong Hou、Zhiyuan Li、Hongchao Guo、Jiangchun Zhong、Min Wang
DOI:10.1016/j.tetasy.2009.07.050
日期:2009.9
A new amino alcohol with a chiral cyclopropane backbone has been developed and used in the catalyticasymmetric diethylzinc addition to various types of α-ketoesters. This cyclopropane-based chiral amino alcohol shows moderate enantioselectivity in the addition of organozinc to α-ketoesters. For dimethylzinc addition to α-ketoesters, up to 81% ee are obtained, respectively.
An enantioselective addition of arylboronic acids and α‐ketoesters promoted by a Rhodium(I)‐chiral diene catalyst is reported. The transformation proceeds regioselectively in the presence of as low as 0.5 mol% of the catalyst generated in situ from a Rhodium(I) salt and diene L1, which is a bicyclo[2.2.1] ligand scaffold bearing 2,5 dinaphthyl substituents, to afford tertiary chiral α‐hydroxy esters