Bifunctional chiral 4-aryl-pyridine-N-oxides (ArPNO) were reported for the acylative kinetic resolution of 3-hydroxy-3-substituted oxindoles, where the oxygen acts as the nucleophilic site. Using less sterically hindered acetic anhydride, both the recovered tertiary heterocyclic alcohols and the ester products exhibited good to excellent results with s-factors up to 167. Control experiments supported
据报道,双功能手性 4-芳基-
吡啶-N-氧化物 (Ar
PNO) 用于 3-羟基-3-取代的羟
吲哚的酰化动力学拆分,其中氧充当亲核位点。使用较少空间位阻的
乙酸酐,回收的叔杂
环醇和酯产物都表现出良好至优异的结果,s因子高达 167。对照实验支持双重活化方式,其中N-氧化物基团和 N-H 质子在Ar
PNO 对于高选择性和增强催化反应性至关重要。与广泛使用的手性 NHC、异
硫属元素
脲和
DMAP 催化剂相比,我们发现手性 Ar
PNO 在叔醇的动力学拆分中也是有效的有机催化剂。