Catalytic Asymmetric [3+2] Cycloadditions of C‐3 Unsubstituted 2‐Indolylmethanols: Regio‐, Diastereo‐ and Enantioselective Construction of the Cyclopenta[<i>b</i>]indole Framework

Abstract

Abstract The first catalytic asymmetric [3+2] cycloaddition of 2‐indolylmethanols with 3‐vinylindoles has been established, which makes use of C‐3 unsubstituted 2‐indolylmethanol as a C 3 building block in the presence of a chiral phosphoric acid. By using this strategy, biologically important cyclopenta[ b ]indole frameworks were efficiently constructed with regiospecificity in high yields (up to 99%), excellent diastereo‐ and enantioselectivities (up to &gt;95:5 dr , 96:4 er ). This reaction not only represents the first catalytic asymmetric [3+2] cycloaddition of C‐3 unsubstituted 2‐indolylmethanols, but also has confronted the great challenges in 2‐indolylmethanol‐involved enantioselective transformations. magnified image