Cobalt catalyzed carbonylation of unactivated C(sp3)–H bonds† †Electronic supplementary information (ESI) available. CCDC 1507203 (2t) & 1507204 (2a). For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc05026c Click here for additional data file. Click here for additional data file.

A general efficient regioselective cobalt catalyzed carbonylation of unactivated C(sp)–H bonds of aliphatic amides was demonstrated using atmospheric (1–2 atm) carbon monoxide as a C1 source. This straightforward approach provides access to a-spiral succinimide regioselectively in a good yield. Cobalt catalyzed sp C–H bond carbonylation is reported for the first time including the functionalization of (b)-C–H bonds of a-1 , 2 , 3 carbons and even internal (b)-C–H bonds. Our initial mechanistic investigation reveals that the C–H activation step is irreversible and will possibly be the rate determining step.