Electrochemical Functional-Group-Tolerant Shono-type Oxidation of Cyclic Carbamates Enabled by Aminoxyl Mediators

An electrochemical method has been developed for α-oxygenations of cyclic carbamates by using a bicyclic aminoxyl as a mediator and water as the nucleophile. The mediated electrochemical process enables substrate oxygenation to proceed at a potential that is approximately 1 V lower than the redox potential of the carbamate substrate. This feature allows for functional-group compatibility that is inaccessible with conventional Shono oxidations, which proceed by direct electrochemical substrate oxidation. This reaction also represents the first α-functionalization of non-activated cyclic carbamates with oxoammonium oxidants.