Catalytic Enantioselective Methylene C(sp3)–H Hydroxylation Using a Chiral Manganese Complex/Carboxylic Acid System
Catalytic Enantioselective Methylene C(sp3)–H Hydroxylation Using a Chiral Manganese Complex/Carboxylic Acid System
复制标题
使用手性锰络合物/羧酸系统催化对映选择性亚甲基 C(sp3)→H 羟基化
DOI：
10.1021/acs.orglett.0c03585
复制
发表时间：
2020
期刊：
影响因子：
5.2
通讯作者：
Wei Sun
中科院分区：
文献类型：
--
作者：
Qiangsheng Sun;Wei Sun
以高度非对映和对映选择性的方式实现直接C-H羟基化仍然是一个具有挑战性的目标。该反应主要受到所产生的醇的过氧化的可能性以及低立体选择性的阻碍。在此，我们提出了一种不对称选择性的苄基C-H羟基化催化锰配合物，过氧化氢，和羧酸在2，2，2-三氟乙醇。苄醇类化合物具有良好的非对映选择性（高达95：5）和对映选择性（高达95%ee）。作为本工作的一个亮点，通过调节羧酸添加剂的量可以实现C-H羟基化的高非对映选择性。
Achieving direct C–H hydroxylation in a highly diastereo- and enantioselective manner is still a challenging goal. This reaction is mainly hindered by the potential for overoxidation of the generated alcohols as well as low stereoselectivity. Herein, we present an enantioselective benzylic C–H hydroxylation catalyzed by a manganese complex, H2O2, and a carboxylic acid in 2,2,2-trifluoroethanol. The benzylic alcohols were successfully furnished in excellent diastereoselectivities (up to >95:5) and enantioselectivities (up to 95% ee). As a highlight of this work, high diastereoselectivity of C–H hydroxylation could be achieved by tuning the amount of carboxylic acid additive.