Pd(ii)-catalyzed ligand controlled synthesis of methyl 1-benzyl-1H-indole-3-carboxylates and bis(1-benzyl-1H-indol-3-yl)methanones?

Organic & Biomolecular Chemistry Pub Date: 2014-05-07 DOI: 10.1039/C4OB00714J

Abstract

A simple change of ligand and solvent allows controlled, effective switching between cyclization–carbonylation and cyclization–carbonylation–cyclization-coupling (CCC-coupling) reactions of 2-alkynylanilines catalyzed by palladium(II). The use of a [Pd(tfa)2(box)] catalyst in iPrOH afforded symmetrical ketones bearing two indoles in good yields; replacing the catalyst and solvent with Pd(tfa)2 and DMSO–MeOH led to the formation of methyl 1-benzyl-1H-indole-3-carboxylates in good yields.

Graphical abstract: Pd(ii)-catalyzed ligand controlled synthesis of methyl 1-benzyl-1H-indole-3-carboxylates and bis(1-benzyl-1H-indol-3-yl)methanones
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