EFFICIENT SYNTHESES OF SUBSTITUTED CARBAZOLES AND CYCLOPENT[B]INDOLESFROM 1-METHYL-3-(BENZOTRIAZOL-1-YLMETHYL)INDOLE

1-Methyl-3-(benzotriazol-1-ylmethyl)indole (1)undergoes lithiation and 1,4-addition with a variety of alpha,beta-unsaturated ketones and ald ehydes. Subsequent treatment with an acidic resin in refluxing 1,4-dio xane causes intramolecular cyclization followed by aromatization to fu rnish a wide range of 1.3-di-, 2,3-di- and 1,2,3-trisubstituted carbaz oles 6a-j and 8 in moderate to excellent yields. NMR study is describe d to discriminate between structures of types 6 and 8 on the basis of H-1-C-13 long-range correlation. Treatment of 1 with styrenes in the p resence of zinc bromide results in formal [3+2] cycloaddition to give cyclopent[b]indoles 14a-c in good yields. When 1 is first lithiated an d reacts with electrophiles, the resulting alkylation products undergo similar [3+2] additions with styrenes to give 1-functionalized cyclop ent[b]indoles 15 and 16 with a high degree of stereoselectivity.