Regiospecific Functionalization of Azacalixaromatics through Copper-Mediated Aryl C–H Activation and C–O Bond Formation

Regiospecific functionalization of tetraazacalix[1]arene[3]pyridines at the lower rim position of the benzene ring was achieved conveniently from their cross-coupling reaction with both aliphatic alcohols including chiral primary and secondary alcohols and phenol derivatives through the Cu(ClO4)2-mediated aerobic aryl C–H activation, which gave structurally well-defined aryl–Cu(III) intermediates and a subsequent C–O bond formation reaction under very mild conditions.