Lewis Base Catalyzed Aldol Additions of Chiral Trichlorosilyl Enolates and Silyl Enol Ethers
作者:Scott E. Denmark、Shinji Fujimori、Son M. Pham
DOI:10.1021/jo051930+
日期:2005.12.1
diastereodifferentiation in chiral Lewis base catalyzed aldol additions using chiral enoxysilanes derived from lactate, 3-hydroxyisobutyrate, and 3-hydroxybutyrate have been investigated. Trichlorosilyl enolates derived from the chiral methyl and ethyl ketones were subjected to aldolization in the presence of phosphoramides, and the intrinsic selectivity of these enolates and the external stereoinduction
已经研究了使用衍生自乳酸酯,3-羟基异丁酸酯和3-羟基丁酸酯的手性环氧硅烷在手性Lewis碱催化的醛醇加成中双重非对映异构化的结果。在磷酰胺存在下,将手性甲基和乙基酮制得的三氯甲硅烷基烯醇化物进行醛醇缩合,研究了这些烯醇化物的内在选择性和手性催化剂的外部立体诱导。在与乳酸衍生的烯醇酸酯的反应中,强烈的内部立体诱导作用占添加醛醇的立体化学结果。对于3-羟基异丁酸酯和3-羟基丁酸酯衍生的烯醇化物,观察到催化剂控制的非对映选择性,并且驻留的立体异构中心发挥了边际影响。4 /双磷酰胺催化的醛醇加成反应,还研究了双非对映异构作用。该过程的整体非对映选择再次由催化剂的强烈外部影响来控制。