Vinylborane Formation in Rhodium-Catalyzed Hydroboration of Vinylarenes. Mechanism versus Borane Structure and Relationship to Silation
作者:John M. Brown、Guy C. Lloyd-Jones
DOI:10.1021/ja00082a006
日期:1994.2
Attempted catalytic hydroboration of (4-methoxyphenyl)ethene 1 with R,R-3-isopropyl-4-methyl-5-phenyl-1,3,2-oxazaborolidine 6 proceeded extremely slowly relative to the 3-methyl analog 2 derived from φ-ephedrine when diphosphinerhodium complexes were employed. With phosphine-free rhodium catalysts, especially the 4-methoxyphenylethene complex 7, the reaction proceeded rapidly and quantitatively to
(4-甲氧基苯基)乙烯 1 与 R,R-3-isopropyl-4-methyl-5-phenyl-1,3,2-oxazaborolidine 6 的催化硼氢化反应相对于衍生自 φ 的 3-甲基类似物 2 进行得非常缓慢- 麻黄碱,当使用二膦铑配合物时。使用不含膦的铑催化剂,尤其是 4-甲氧基苯基乙烯配合物 7,反应进行快速定量,仅得到等摩尔量的相应 (E)-乙烯基硼烷 9 和 4-甲氧基乙基苯 8