Highly Enantioselective Synthesis of Chiral Hydrocarbazole-4-Carbaldehyde Scaffolds and Constrained Analogue of MS-245 via Iminium Catalysis at Elevated Temperatures

The chiral hydrocarbazole-4-carbaldehyde scaffold is a privileged structural motif present in numerous biologically active indole alkaloids. Nevertheless, catalytic asymmetric access to this motif remains an unsolved challenge. Herein, we report the successful construction of a chiral hydrocarbazole-4-carbaldehyde scaffold via asymmetric iminium catalysis under elevated temperatures, affording unprecedented regioselective and dearomatizing hydrocarbazole structures. Subsequently, the synthesis of MS-245 constrained analogues was efficiently accomplished.