Scope and Mechanism of the Pt-Catalyzed Enantioselective Diboration of Monosubstituted Alkenes
作者:John R. Coombs、Fredrik Haeffner、Laura T. Kliman、James P. Morken
DOI:10.1021/ja4041016
日期:2013.7.31
The Pt-catalyzed enantioselective diboration of terminal alkenes can be accomplished in an enantioselective fashion in the presence of chiral phosphonite ligands. Optimal procedures and the substrate scope of this transformation are fully investigated. Reaction progress kinetic analysis and kinetic isotope effects suggest that the stereodefining step in the catalytic cycle is olefin migratory insertion
Pt 催化的末端烯烃的对映选择性二硼化可以在手性亚膦酸酯配体存在下以对映选择性方式完成。对这种转化的最佳程序和底物范围进行了充分研究。反应进程动力学分析和动力学同位素效应表明催化循环中的立体定义步骤是烯烃迁移插入 Pt-B 键。密度泛函理论分析与其他实验数据相结合,表明插入反应将铂定位在基板的内部碳上。该反应的立体化学模型得到了改进,该模型既符合这些特征又符合 Pt-配体复合物的晶体结构。