Asymmetric oxidative coupling of hydroxycarbazoles: Facile synthesis of (+)-bi-2-hydroxy-3-methylcarbazole.

Asymmetric oxidative coupling reactions of hydroxycarbazoles have been established using a chiral dinuclear vanadium complex. To demonstrate the utility of vanadium-catalyzed reactions, we have used them to synthesize (+)-bi-2-hydroxy-3-carbazole in three steps from cyclohexanone and commercially available aniline derivatives.