Transition Metals in Organic Synthesis, Part 82. First Total Synthesis of Methyl 6-Methoxycarbazole-3-carboxylate, Glycomaurrol, the Anti-TB Active Micromeline, and the Furo[2,3-c]carbazole Alkaloid Eustifoline-D

Abstract

The palladium(0)-catalyzed amination followed by palladium(II)-catalyzed oxidative cyclization of the resulting diarylamine provides a short route to a series of 6-oxygenated carbazole alkaloids: glycozoline, 3-formyl-6-methoxycarbazole, methyl 6methoxycarbazole-3-carboxylate, glycozolinine (glycozolinol), glycomaurrol, micromeline, and eustifoline-D.

One‐Pot Synthesis of Functionalized Carbazoles and β‐Carbolines via Diethyl Azodicarboxylate Mediated Dehydrogenative Aromatization in Deep Eutectic Solvent

“…Moreover, di‐substitution on both the benzene ring with the competitive substituents also suited well to afford the desired product 5 p with 95 % of yield. This sustainable protocol demonstrates its utility in synthesis of naturally occurring carbazole alkaloids like 3‐methylcarbazole ( 5 b) , [59] glycozoline ( 5 h) [60] with excellent yields significantly reduced reaction time.…”

“…3-methylcarbazole (5 b), [59] glycozoline (5 h) [60] with excellent yields significantly reduced reaction time. Encouraged by the above method, we shifted our attention to apply the same strategy for the synthesis β-carbolines via dehydrogenative aromatization (Scheme 4).…”

Palladium-Catalyzed Synthesis of Natural and Unnatural 2-, 5-, and 7-Oxygenated Carbazole Alkaloids from N-Arylcyclohexane Enaminones

“…The final cyclization step of diarylamines 5a – e was successfully carried out by following the protocol originally developed by Knölker and coworkers [40,56,57], later applied by others [28,29], and optimized in our syntheses of natural carbazoles [37,44]. Thus, the conversion of the series 5a – c and 5e into the carbazole derivatives 1h – k resulted in good yields (80%–92%) (Table 3).…”