A Hydrazone‐Based exo ‐Directing‐Group Strategy for β C−H Oxidation of Aliphatic Amines

Described is a new hydrazone‐based exo ‐directing group (DG) strategy developed for the functionalization of unactivated primary β C−H bonds of aliphatic amines. Conveniently synthesized from protected primary amines, the hydrazone DGs are shown to site‐selectively promote the β‐acetoxylation and tosyloxylation via five‐membered exo ‐palladacycles. Amines with a wide scope of skeletons and functional groups are tolerated. Moreover, the hydrazone DG can be readily removed, and a one‐pot C−H acetoxylation/DG removal protocol was also discovered.