First total synthesis of the biologically active 2,7-dioxygenated tricyclic carbazole alkaloids 7-methoxy-O-methylmukonal, clausine H (clauszoline-C), clausine K (clauszoline-J) and clausine O.

Using the iron-mediated arylamine cyclization as the key step we have achieved a short and highly efficient access to the biologically active 2,7-dioxygenated tricyclic carbazole alkaloids 7-methoxy-O-methylmukonal, clausine H (clauszoline-C), clausine K (clauszoline-J) and clausine O.