Photochemical regioselective C–H arylation of imidazo[1,2-a]pyridine derivatives using chlorophyll as a biocatalyst and diazonium salts

Abstract

This communication describes the development of a mild method for the arylation of imidazo[1,2-a]pyridine with diazonium salt derivatives and using chlorophyll as a biocatalyst via visible-light catalysis. Natural pigments such as chlorophyll are used as a green photosensitizer and an environmentally benign catalyst. The general and easy procedure provides a transition-metal-free alternative for the formation of 2,3-diaryl imidazo[1,2-a]pyridine derivatives at ambient temperature in good to excellent yields.