报道了一种通过配体控制的 O-to-C 异构化制备未季铵化 C 结合硼烯醇化物的通用和简便方法。使用该协议,首次以纯形式分离了 C 结合的频哪醇烯醇化物,并通过核磁共振光谱和 X 射线晶体学进行了充分表征。与一般看法相反,这种 C-硼烯醇化物是稳定的,在硼处没有配位饱和。此外,C-硼烯醇化物呈现出与O-硼烯醇化物不同的反应性,并且证明了它们在CO和CC键形成中的应用。
Regioselective synthesis of 2-arylpropionic esters by palladium-catalyzed hydroesterification of styrene derivatives in molten salt media
作者:Danilo Zim、Roberto F. de Souza、Jairton Dupont、Adriano L. Monteiro
DOI:10.1016/s0040-4039(98)01551-2
日期:1998.9
The palladium-catalyzed hydroesterification of styrene derivatives is performed in a two-phase system composed of 1-n-butyl-3-methylimidazoliumtetrafluoroborate salt (ionic phase) and isopropanol/cyclohexane (organic phase). Very high regioselectivities in 2-arylpropionic esters (≥99.5%) are obtained using a catalytic system composed of PdCl2(PhCN)2, (+)-neomenthyldiphenylphosphine (NMDPP) and p-toluenesulfonic