Synthesis of the pyrrolo[2,3-c]carbazole core of the dictyodendrins

The pyrrolo[2,3-c] carbazole 1, the common core of the marine alkaloids known as the dictyodendrins, has been synthesised. The sequence is based on a Suzuki cross-coupling reaction between the pyrrole fragment 2 and the indole fragment 3, followed by tandem photochemical 6 pi-electrocyclisation/aromatisation.