Palladium(ii) catalyzed site-selective C-H olefination of imidazo[1,2-a]pyridines

Herein, we disclose an efficient Pd(ii)-catalyzed site selective C8 alkenylation of imidazo[1,2-a]pyridines with electronically biased olefinic substrates. Notably, besides the presence of four C-H sites available, selective mono-alkenylation was achieved by N-chelation overriding O-chelation. The versatility and scalability of the catalysis enabled the selective late-stage functionalization of a marketed drug, zolimidine. Various substituted heteroaryl alkenes can be afforded with moderate to good yields with high C8 regioselectivity.

Automated summary

This study presents an efficient Pd(II)-catalyzed selective C8 alkenylation of imidazo[1,2-a]pyridines using electronically biased olefinic substrates. Selective mono-alkenylation was achieved through N-chelation overriding O-chelation at four available C-H sites, enabling late-stage functionalization of the marketed drug zolimidine with high C8 regioselectivity. Various substituted heteroaryl alkenes can be obtained with moderate to good yields.