NMPA Key Laboratory for Research and Evaluation of Innovative Drug, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Org Biomol Chem. 2022 Aug 17;20(32):6351-6355. doi: 10.1039/d2ob01205g.
Bifunctional chiral 4-aryl-pyridine--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 -factors up to 167. Control experiments supported the dual activation manner, where the -oxide group and N-H proton in ArPNO were crucial for high selectivity and enhanced catalytic reactivity. Compared with the extensively used chiral NHC, isochalcogenourea, and DMAP catalysts, we found that chiral ArPNO were also efficient organocatalysts in the kinetic resolution of tertiary alcohols.
双功能手性 4-芳基-吡啶-N-氧化物（ArPNO）被报道用于 3-羟基-3-取代的氧化吲哚的酰基动力学拆分，其中氧原子作为亲核位点。使用位阻较小的乙酸酐，回收的叔杂环醇和酯产物均表现出良好到优秀的结果，-因子高达 167。控制实验支持双重活化方式，其中 ArPNO 中的-氧化物基团和 N-H 质子对于高选择性和增强的催化反应性至关重要。与广泛使用的手性 NHC、异同多硫脲和 DMAP 催化剂相比，我们发现手性 ArPNO 也是叔醇动力学拆分的有效有机催化剂。
