An Improved Approach to the Synthesis of Tetracyclic 20-Deethyl-4-demethyldasycarpidone and 20-Deethyldasycarpidone

An efficient method has been reported for the synthesis of 20-deethyl-4-demethyldasycarpidone and 20-deethyldasycarpidone by tetracholoro-1,4-benzoquinone (TCB)-mediated cyclization of intermediate tetrahydrocarbazole obtained from tert-butyl [2-methyl-1-(4-methylbenzenesulfonyl)-1H-indol-3-yl]methyl carbonate. 2-[9-(4-Methylbenzenesulfonyl)-2,3,4,9-tetrahydro-1H-carbazol-2-yl]acetonitrile as the ABCD sub-struc-ture of Strychnos alkaloid family has been synthesized for the first time in a different way.