Practical method for synthesis of 2,3-disubstituted indole derivatives promoted by β-(benzotriazol-1-yl)allylic O-stannyl ketyl radicals

Treatment of beta-aryl-beta-(benzotriazol-1-yl)-alpha-primary alkyl (or aryl)-alpha,beta-unsaturated ketones 1 with n-Bu3SnH (4 equiv) in a catalytic amount of AlBN in PhH at reflux afforded 3-alkyl (or aryl)-2-arylindoles 8 in good yields. However, when tert-butyl group is bonded at alpha-position, 3-acyl (or aroyl)-2-arylindoles 9 were obtained as major products along with phenanthridines 5 as minor products. (C) 2009 Elsevier Ltd. All rights reserved.