Enantioselective Synthesis of Indolizidines Bearing Quaternary Substituted Stereocenters via Rhodium-Catalyzed [2 + 2 + 2] Cycloaddition of Alkenyl Isocyanates and Terminal Alkynes
作者:Ernest E. Lee、Tomislav Rovis
DOI:10.1021/ol800086s
日期:2008.3.1
An enantioselective synthesis of indolizidines bearing quaternary substituted stereocenters by way of a rhodium-catalyzed [2+2+2] cycloaddition of substituted alkenyl isocyanates and terminal alkynes is described. The reaction provides lactam products using aliphatic alkynes, whereas aryl alkynes give rise to vinylogous amide products. Through modification of the phosphoramidite ligand, high levels
描述了通过铑催化的取代烯基异氰酸酯和末端炔烃的 [2+2+2] 环加成反应,对映选择性合成带有季取代立体中心的吲哚里西啶。该反应使用脂肪族炔烃提供内酰胺产物,而芳基炔烃产生乙烯基酰胺产物。通过亚磷酰胺配体的修饰,两种产物都获得了高水平的对映选择性、区域选择性和产物选择性。