Enantioselective Thiourea-Catalyzed Additions to Oxocarbenium Ions
作者:Sarah E. Reisman、Abigail G. Doyle、Eric N. Jacobsen
DOI:10.1021/ja801514m
日期:2008.6.1
Asymmetric, catalytic reactions of oxocarbeniumions 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 oxocarbeniumion is invoked. Catalysts bearing tertiary benzylic amide groups afforded highest enantioselectivities