Mn(II)-Catalyzed C-H Alkylation of Imidazopyridines and N-Heteroarenes via Decarbonylative and Cross-Dehydrogenative Coupling.

A Mn(II)-catalyzed efficient C-H alkylation of imidazoheterocycles and N-heteroarenes with aliphatic aldehydes has been developed via oxidative decarbonylation. Other alkylating agents such as cyclic alkanes, ethers, and alcohols also coupled with N-heteroarenes through cross-dehydrogenative coupling. Regioselectively C5-alkylated imidazoheterocycles were synthesized in good yields. Experimental results show that radical pathway might be involved in this reaction.