作者:Sarah E. Reisman、Abigail G. Doyle、Eric N. Jacobsen
DOI:10.1021/ja801514m
日期:2008.6.1
Asymmetric, catalytic reactions of oxocarbenium ions are reported. Simple, chiral urea and thiourea derivatives are shown to catalyze the enantioselective substitution of silyl ketene acetals onto 1-chloroisochromans. A mechanism involving anion binding by the chiral catalyst to generate a reactive oxocarbenium ion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities
报道了氧碳鎓离子的不对称催化反应。简单的手性尿素和硫脲衍生物可催化甲硅烷基乙烯酮缩醛对 1-氯异色满的对映选择性取代。涉及通过手性催化剂结合阴离子以产生活性氧代碳鎓离子的机制被调用。带有叔苄基酰胺基团的催化剂具有最高的对映选择性,最佳结构来自富含对映体的 2-芳基吡咯烷衍生物。