Overcoming the Challenges Towards Selective C(6)-H Alkylation of 2- Pyridone with Maleimide through Mn(I)-Catalyzed C-H bond Activation: Zn assisted Unexpected Migration of Directing group

Abstract

An earth-abundant and inexpensive Mn(I)-catalyzed alkylation of 2-pyridone with maleimide has been reported for the first time, in contrast to previously reported Diels-alder product. The directing group was easily removed after functionalization. Notably, unexpected migration of pyridine ring has been discovered in presence of zinc, and acetic acid conditions, which also provides a new route to quaternary carbon centers which contain two heterocycles. Furthermore, single crystal X-ray and HRMS revealed a five-membered manganacycle intermediate. This methodology tolerates a wide variety of functional groups delivering the alkylated products in moderate to excellent yields.