Three-component tandem reaction involving acid chlorides, terminal alkynes, and 2-aminoindole hydrochlorides: synthesis of α-carboline derivatives in aqueous conditions via regioselective [3 + 3] cyclocondensation.

An efficient synthesis toward highly diversified α-carboline derivatives via a three-component tandem reaction using acid chlorides, terminal alkynes, and 2-aminoindole hydrochlorides has been described. The salient feature of the one-pot strategy involves regioselective [3 + 3]-cyclocondensation and the presence of water in the reaction medium to facilitate cyclization. Nonaqueous conditions furnished products in poor yields.