Access to tetrahydrocarbazoles via a photocatalyzed cascade decarboxylation/addition/cyclization reaction

Abstract

An efficient photocatalyzed decarboxylative coupling of indolepropionic acid NHPI esters with α,β-unsaturated carbonyl compounds has been developed. Various α,β-unsaturated carbonyl compounds including esters, ketones, aldehydes, and amides showed good compatibility, providing structurally diverse tetrahydrocarbazoles in moderate to good yields. This approach features a wide substrate scope and mild reaction conditions. The synthetic value of this method was further demonstrated by the post-transformation of the product into carbazole.