Lewis Base Activation of Lewis Acids: Catalytic, Enantioselective Addition of Silyl Ketene Acetals to Aldehydes
作者:Scott E. Denmark、Gregory L. Beutner、Thomas Wynn、Martin D. Eastgate
DOI:10.1021/ja047339w
日期:2005.3.1
The concept of Lewis base activation of Lewis acids has been reduced to practice for catalysis of the aldol reaction of silyl ketene acetals and silyl dienol ethers with aldehydes. The weakly acidic species, silicon tetrachloride (SiCl4), can be activated by binding of a strongly Lewis basic chiral phosphoramide, leading to in situ formation of a chiral Lewis acid. This species has proven to be a competent
路易斯酸的路易斯碱活化的概念已被简化用于催化甲硅烷基乙烯酮缩醛和甲硅烷基二烯醇醚与醛的羟醛反应。弱酸性物质四氯化硅 (SiCl4) 可以通过结合强路易斯碱性手性磷酰胺而被激活,导致手性路易斯酸的原位形成。该物质已被证明是将乙酸酯、丙酸酯和异丁酸酯衍生的甲硅烷基乙烯酮缩醛与共轭和非共轭醛进行羟醛加成反应的有效催化剂。此外,还证明了甲硅烷基二烯醇醚的乙烯基羟醛反应。高水平的区域-,抗非对映-,