SYNTHESIS OF A REBECCAMYCIN-RELATED INDOLO[2,3-A]CARBAZOLE BY PALLADIUM(0) CATALYZED POLYANNULATION

The assembly of the parent Indolo[2,3-a]carbazole ring system, common to rebeccamycin and arcyriaflavin A, is efficiently accomplished by th e discovery of a novel palladium(0)-catalyzed polyannulation reaction, wherein 4 bonds are formed in a single step from a simple monocyclic 1,3-diacetylene precursor. This chemistry further demonstrates the pow er of palladium(0) in the execution of complex synthetic organic chemi stry, and also provides a novel approach to rite synthesis of Indolo[2 ,3-a]carbazole alkaloids, an increasingly important class of bioactive natural products.