Gold(I)‐Catalyzed Enantioselective Synthesis of Tetrahydrocarbazoles through Dearomative [4+2] Cycloadditions of 3/2‐Substituted 2/3‐Vinylindoles

Abstract The gold‐catalyzed synthesis of tetrahydrocarbazoles through dearomative [4+2] cycloaddition reactions of 3/2‐substituted 2/3‐vinylindoles with allenamides is reported. In particular, we optimized the enantioselective variant of these cycloadditions. Using allenamides as dienophiles 3‐substituted 2‐vinylindoles gave the corresponding carbazoles with high chemo‐, regio‐ and enantioselectivity. Good results were obtained also with 2‐methyl 3‐vinylindoles even if mixtures of ( Z ) and ( E ) isomers were isolated in high er and in excellent overall yields. magnified image