[(S)-BINAP]PdBr2-catalyzed direct synthesis of 2,3-disubstituted indoles via a tandem reaction between arylamines and α-diketones

A direct PdBr2(BINAP)-complex catalyzed method has been developed to produce 2,3-disubstituted indoles by the reaction of arylamines with alpha-diketones under reductive (H-2) conditions. The synthetic methodology involves a tandem reaction of three steps and all the organic intermediates were isolated and characterized, the reduction products in this sequence are chiral and present interesting enantiomeric excess. This report constitutes a new and different route to synthesize indoles and a plausible mechanism is also suggested. (C) 2011 Elsevier Ltd. All rights reserved.