Catalytic migratory oxidative coupling of nitrones through an outer-sphere C(sp3)-H activation process.

Outer-sphere redox catalysis is key to efficient C-H activation, which has attracted increased interest in organic chemistry. In this account, we describe a Cu(I) -catalyzed oxidative coupling between nitrones and various ethers or amines as an example. Predictable site-selective C-C bond formation was achieved through activation of the C-H bonds in each coupling partner and the migration of a C-N double bond. Mechanistic studies strongly suggested that the reaction proceeded via an oxonium/iminium cation species as the key intermediate. The mechanistic information allows for future extension of outer-sphere redox catalysis.