A Novel Total Synthesis of Antibiotic Carbazole Alkaloid Carbazomycin G

A total synthesis of carbazomycin G (1) has been newly completed in seven steps. The 1,3-dioxygenated carbazole (4) via the 3-methoxy-1-methoxymethyloxycarbazole (11) as a synthetic precursor was synthesized by using the allene-mediated electrocyclic reaction of a 6π electron system generating from the 2-propargylindole derivative (10), which was derived from the 3-vinylindole (8) in three steps. Finally, the oxidation of the phenol (4) followed by the addition of methyl lithium to the carbazole-1,4-quinone (3) provided carbazomycin G (1).