α-Lithiation of N-Alkylcarbazoles: Preparation of N-(E)-Styrylcarbazole

Article abstract of DOI:10.1021/jo00209a001

Alkylation of carbazole with <(chloromethyl)thio>benzene gave the key intermediate N-<(phenylthio)methyl>carbazole (2).Treatment of 2 with n-butyllithium at low temperature gave an α-lithio derivative 3, which reacted with a variety of electrophiles, affording N-<(phenylthio)alkyl>carbazoles 4a-g.Removal of the activating phenylthio group in 4a-g was achieved by Raney nickel desulfurization.Three successful routes to the novel N-(E)-styrylcarbazole (10) are described. 1H NMR and 13C NMR assignments of N-alkylcarbazoles are discussed.