Boron aldol additions with erythrulose derivatives: dependence of stereoselectivity on the type of protecting group
作者:Miguel Carda、Eva Falomir、Juan Murga、Encarnación Castillo、Florenci González、J. Alberto Marco
DOI:10.1016/s0040-4039(99)01380-5
日期:1999.9
Boron aldol additions of 1-O-silylated 3,4-di-O-benzyl- and 3,4-di-O-benzoyl-l-erythrulose and achiral aldehydes using dicyclohexylboron chloride have been investigated. The dibenzyl derivative gave syn/syn stereoisomers with high stereoselectivity, whereas the dibenzoyl derivative gave syn/anti stereoisomers. It is believed that, while the dibenzoyl erythrulose gives rise to the E enolate in the presence
已经研究了使用二环己基氯化硼对1 - O-甲硅烷基化的3,4-二-O-苄基-和3,4-二-O-苯甲酰基-1-赤藓糖和非手性醛的硼醇醛加成。二苄基衍生物给出了具有高立体选择性的顺式/顺式立体异构体,而二苯甲酰基衍生物给出了顺式/反式立体异构体。据信,虽然二苯甲酰赤藓酮糖产生了È烯醇化物中的dicyclohexylboron酰氯存在,因为通常与该试剂观察到,只有ž形成在二苄基衍生物的情况下的烯醇化物。