Annulation of α-bromocinnamaldehydes to access 3-formyl-imidazo[1,2- α ]pyridines and pyrimidines under transition metal-free conditions.

An environmentally friendly and transition metal-free method for the annulation of α-bromocinnamaldehydes was established. 3-Formyl-imidazo[1,2- α ]pyridines and pyrimidines were obtained in moderate to excellent yields. This approach features easily available starting materials, transition metal-free conditions, good functional group tolerance and operational simplicity.