Direct synthesis of highly fused perimidines by copper(I)-catalyzed hydroamination of 2-ethynylbenzaldehydes

A novel synthesis of highly fused perimidine derivatives was achieved in two steps from 2-alkynylbenzaldehydes. Copper-catalyzed annulation of 2-[(2-bromophenyl)ethynyl]benzaldehydes with 1,8-diaminonaphthalene produced dihydroisoquinolino[2,1-a]perimidines bearing a 2-bromophenyl group. Subsequent palladium-catalyzed C-H arylation provided dibenzo[1,2:7,8]quinolizino[3,4,5,6-kla]perimidine derivatives in moderate to good yields.