Catalytic Asymmetric Synthesis of 3,3′-Diaryloxindoles as Triarylmethanes with a Chiral All-Carbon Quaternary Center: Phase-Transfer-Catalyzed S<sub>N</sub>Ar Reaction
Catalyticasymmetric synthesis of unsymmetrical triarylmethanes with a chiral all‐carbon quaternarycenter was achieved by using a chiral bifunctionalquaternary phosphonium bromide catalyst in the SNAr reaction of 3‐aryloxindoles under phase‐transfer conditions. The presence of a urea moiety in the chiral phase‐transfer catalyst was important for obtaining high enantioselectivity in this reaction
在相转移条件下,通过手性双官能季铵溴化甲烷催化剂在3-芳基氧吲哚的S N Ar反应中使用手性双碳四级溴化catalyst催化剂,实现了具有手性全碳季中心的不对称三芳基甲烷的催化不对称合成。手性相转移催化剂中尿素部分的存在对于在该反应中获得高对映选择性很重要。