Synthesis of 1,2-Disubstituted-3-thioindoles by the Madelung Reaction

Abstract

1,2-Disubstituted-3-thioindoles were synthesized by the Madelung reaction from the available starting compounds benzyl sulfides. The synthesis under the optimized conditions (0.2 M benzyl sulfide in THF, 2 equiv LDA) gave 1,2-disubstituted-3-thioindoles with electron-donor and electron-acceptor substituents in the 5 and 6 positions, as well as with aromatic and aliphatic substituents on the sulfur atom in high yields (62–93%).