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-Michael reaction 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 Lewis acid. (2) Ketene silyl acetals 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
设计了高度非对映选择性的Mukaiyama-Michael反应。为此目的,抑制电子转移过程至关重要,应满足以下条件。(1)使用TiCl 4作为路易斯酸。(2)烯丙基甲硅烷基乙缩醛具有庞大的甲硅烷氧基和/或烷氧基。(3)α-烯酮具有庞大的酰基。在这些条件下,可获得高达99:1的极好的顺选择性。当减小烷氧基的大小时,选择性逆于反偏好。