Oxidative Kinetic Resolution of Cyclic Benzylic Ethers

A manganese‐catalyzed oxidative kinetic resolution of cyclic benzylic ethers through asymmetric C(sp3)−H oxidation is reported. The practical approach is applicable to a wide range of 1,3‐dihydroisobenzofurans bearing diverse functional groups and substituent patterns at the α position with extremely efficient enantiodiscrimination. The generality of the strategy was further demonstrated by efficient oxidative kinetic resolution of another type of five‐membered cyclic benzylic ether, 2,3‐dihydrobenzofurans, and six‐membered 6H‐benzo[c]chromenes. Direct late‐stage oxidative kinetic resolution of bioactive molecules that are otherwise difficult to access was further explored. A manganese‐catalyzed kinetic resolution through asymmetric C(sp3)−H oxidation was applied to a wide range of five‐membered 1,3‐dihydroisobenzofurans and 2,3‐dihydrobenzofurans as well as six‐membered 6H‐benzo[c]chromenes bearing diverse α‐substituents with extremely efficient enantiodiscrimination (see scheme). Late‐stage oxidative kinetic resolution of bioactive molecules that are otherwise difficult to access was further demonstrated.