Construction of isoxazolone-fused phenanthridines via Rh-catalyzed cascade C–H activation/cyclization of 3-arylisoxazolones with cyclic 2-diazo-1,3-diketones

Abstract

A Rh(III)-catalyzed cascade C–H activation/intramolecular cyclization of 3-aryl-5-isoxazolones with cyclic 2-diazo-1,3-diketones was described, leading to the formation of isoxazolo[2,3-f]phenanthridine skeletons. The protocol features the simultaneous one-pot formation of two new C–C/C–N bonds and one heterocycle in moderate-to-good yields with good functional group compatibility. It is amenable to large-scale synthesis and further transformation.