Highly chemo- and site-selective C(sp2)–H bond functionalization of aniline and phenol derivatives with aryl/aryl diazo compounds†

An unprecedented chemo- and site-selective para-C(sp²)–H bond functionalization of aniline and phenol derivatives with aryl/aryl diazo compounds was successfully developed. The cooperative catalysis of bismuth(iii) triflate and Brønsted acid promoted this transformation instead of the well-known N–H/O–H insertion, furnishing the corresponding triarylmethane compounds under mild conditions. The protocol features broad substrate scope, excellent chemo- and site-selective C–H bond functionalization, as well as non-noble metal catalysts.