Catalyst-free tandem Michael addition/decarboxylation of (thio)coumarin-3-carboxylic acids with indoles: facile synthesis of indole-3-substituted 3,4-dihydro(thio)coumarins

Abstract

The tandem Michael addition/decarboxylation of (thio)coumarin-3-carboxylic acids with indoles has been developed and the biologically important indole-3-substituted dihydrocoumarins were obtained in good to excellent yields under catalyst-free conditions.