Synthesis of carbazomycin B by radical arylation of benzene

Iodination of 2-methoxy-3,4-dimethyl-5-nitrophenol followed by acetylation yields (6-iodo-2-methoxy-3,4-dimethyl-5-nitrophenyl) acetate. Reduction with iron and acetic acid followed by reaction with methyl chloroformate then provides N-methoxycarbonyl-3-acetoxy-2-iodo-4-methoxy-5,6-dimethylaniline. Treatment of this substance in benzene at reflux with tributyltin hydride and a catalytic quantity of diphenyl diselenide leads to the formation of N-methoxycarbonyl-3-acetoxy-2-(2,5-cyclohexadienyl)-4-methoxy-5,6-dimethylaniline which on exposure to phenylselenenyl bromide affords a phenylselenenyl tetrahydrocarbazole. Oxidation deselenation and rearomatization are achieved by heating with tert-butylhydroperoxide finally affording carbazomycin B after saponification.