Novel approach to remote asymmetric induction in carbonyl addition and related reactions
作者:Gary A. Molander、Joseph P. Haar
DOI:10.1021/ja00054a006
日期:1993.1
Neighboring group participation is postulated to be responsible for high asymmetric induction in the addition of various nucleophiles (e.g., Me 3 SiCN, allylsilane, and allylstannanes) to chiral alkoxy acetals and aldehydes. Thus, oxacarbenium ions generated by treatment of thee substrate with various Lewis acids suffer intramolecular solvation by a neigbboring alkoxy group. This establishe a conformationally
相邻基团的参与被假定为在将各种亲核试剂(例如,Me 3 SiCN、烯丙基硅烷和烯丙基锡烷)添加到手性烷氧基缩醛和醛中时产生高度不对称诱导的原因。因此,通过用各种路易斯酸处理底物产生的氧杂碳鎓离子受到相邻烷氧基的分子内溶剂化。这建立了一个构象定义的环状氧鎓离子中间体,可以被亲核试剂攻击,在该过程中提供高非对映选择性