Synthesis of 2‐Hydroxy‐7‐methylcarbazole, Glycozolicine, Mukoline, Mukolidine, Sansoakamine, Clausine‐H, and Clausine‐K and Structural Revision of Clausine‐TY

A Buchwald–Hartwig amination and palladium(II)-catalyzed oxidative cyclization reaction sequence provided efficient access to a series of oxygenated tricyclic carbazoles. In the present work, this approach was applied to the total syntheses of the naturally occurring carbazole alkaloids 2-hydroxy-7-methylcarbazole, glycozolicine, mukoline, mukolidine, sansoakamine, glycozolidine, clausine-H (clauszoline-C), clausine-K (clauszoline-J), and methyl 2-hydroxy-7-methoxycarbazole-3-carboxylate, which was originally proposed as the structure of clausine-TY. The synthesis of the latter led to the structural reassignment of clausine-TY.