Diastereoselective Mukaiyama-Michael reaction of O,S-ketene silyl acetal
作者:Yukihiro Fujita、Junzo Otera、Shunichi Fukuzumi
DOI:10.1016/0040-4020(96)00479-6
日期:1996.7
The highly diastereoselective Mukaiyama-Michaelreaction has been realized by use of O,S-ketene silylacetals. Of special importance in this reaction is the effective tuning of the stereochemical course simply by changing the double bond geometry of ketenesilylacetals. Thus, both syn- and anti-Michael adducts can be obtained on the synthetically useful levels of stereochemical purity.
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