Catalyst and solvent switched divergent C-H functionalization: oxidative annulation of N-aryl substituted quinazolin-4-amine with alkynes.

The development of site-selective C−H functionalizations/annulations is one of the most challenging practices in synthetic organic chemistry particularly for substrates bearing several similarly reactive C−H bonds. Herein, we describe catalyst and solvent controlled ortho/peri site-selective oxidative annulation of C−H bonds of N-aryl substituted quinazolin-4-amines with internal alkynes. The ortho C−H selective annulation was observed using Pd-catalyst in DMF to give indole-quinazoline derivatives, while, Ru-catalyst in PEG-400 favoured the peri C−H bond annulation exclusively to furnish pyrido-quinazoline derivatives.