Total synthesis of murrastifoline-A by way of the Pd-catalyzed double N-arylation of a carbazolamine with a 2,2′-dibromobiphenyl derivative

The first total synthesis of murrastifoline-A (1), a biscarbazole alkaloid is described. The biscarbazole skeleton of 1 was effectively constructed by the Pd-catalyzed double N-arylation of carbazolamine (bottom-half segment, 3) with dibromobiphenyl derivative (top-half segment, 2) in one-step reaction. Both segments were synthesized starting from 2-amino-5-methylphenol (4).