Diastereoselective aldol condensation of silyl ketene acetal of 2-pyridyl thioester with benzaldehyde
作者:Kwee-Hyun Suh、Dong-Joon Choo
DOI:10.1016/0040-4039(95)01231-6
日期:1995.8
The TiCl4-mediated aldol reaction of the (E)-O-silyl ketene-O,S-acetal derived from 2-pyridyl thioester with benzaldehyde gave exclusively syn-aldol product. In contrast, BF3-mediated reaction afforded the corresponding anti-isomer as a major product. Chelation and acyclic transition state are postulated in order to explain the observed selectivities.
由2-吡啶基硫酯衍生的(E)-O-甲硅烷基烯酮-O,S-缩醛与苯甲醛的TiCl 4介导的醇醛缩合反应仅得到顺式-醛醇缩合产物。相反,BF 3介导的反应提供了相应的反异构体作为主要产物。假定螯合和无环过渡态是为了解释观察到的选择性。