Radical fixation of functionalized carbon resources:: α-sp3C-H carbamoylation of tertiary amines with aryl isocyanates

A new carbamoylation of tertiary amines is reported. This rare C-H transformation features the direct generation of alpha-aminoalkyl radicals from tertiary amines, followed by the addition of the resultant nucleophilic radicals to isocyanates, enabling unique access to N,N-dlalkylated amino acid derivatives. The authors put forward a mechanistic proposal that is based on the isolation of borinamides produced by capturing nitrogen radical intermediates with Et3B. The present transformation provides a novel one-step process for producing mepivacaine, a clinically important local anesthetic, from readily available materials.