Acyclic stereoselection. 46. Stereochemistry of the Michael addition of N,N-disubstituted amide and thioamide enolates to .alpha.,.beta.-unsaturated ketones
The design of diastereoselective Mukaiyama-Michael reaction of ketene silyl acetal
作者:Junzo Otera、Yukihiro Fujita、Shunichi Fukuzumi
DOI:10.1016/0040-4020(96)00478-4
日期:1996.7
The highly diastereoselective Mukaiyama-Michaelreaction has been designed. Suppression of an electron-transfer process is crucial for this purpose and the following conditions should be satisfied. (1) TiCl4 is employed as a Lewisacid. (2) Ketenesilylacetals have bulky siloxy and/or alkoxy group(s). (3) α-Enones have a bulky acyl group. The excellent syn-selectivity up to a 99:1 ratio is attained