Mechanistic Insights into Rhenium‐Catalyzed Regioselective C‐Alkenylation of Phenols with Internal Alkynes
作者:Masahito Murai、Masaki Yamamoto、Kazuhiko Takai
DOI:10.1002/chem.201903910
日期:2019.11.27
rhenium, a metal between the early and late transition metals in the periodic table, was key for the activation of both the soft carbon-carbon triple bond of the alkyne and the hard oxygen atom of the phenol, at the same time. ortho-Selective alkenylation with allenes also provided the corresponding adducts with a substitution pattern different from that obtained by the addition reaction with alkynes.
分离出(μ-芳基氧代)complex络合物,并确认其为rh与炔烃催化with保护的未保护酚的邻链烯基化(C-烯基化)的关键预催化剂。该反应仅提供了邻烯基苯酚。没有观察到对或多烯基化酚的形成和加氢苯氧基化(O-烯基化)产物。几个机理实验排除了经典的Friedel-Crafts型机理,从而导致提出的酚羟基辅助的亲电烯基化是最合理的反应机理。为此,在周期表中使用,(一种在元素周期表中早期和晚期过渡金属之间的金属)是激活炔烃的软碳-碳三键和苯酚的硬氧原子的关键。同一时间。