Total Synthesis of Carbazomycin G by a Thermal Ring Expansion/Self‐Redox Reaction Cascade

Abstract

AbstractThe total synthesis of carbazomycin G (7) has been accomplished in six steps and 26 % overall yield starting from commercially available materials. As an efficient access to the tricyclic skeleton of carbazomycins A–H, an interesting thermal ring expansion/self‐redox reaction cascade of intermediate 11 has been developed in our study. The self‐redox reaction of intermediate 10 can be readily accelerated in the presence of triethylamine, and a plausible reaction mechanism for this process has been proposed. Finally, the synthesis of carbazomycin G was completed by the widely applied regioselective methylation reaction.