Tetrahedron letters

InBr 3-catalyzed sulfonation of indoles: a facile synthesis of 3-sulfonyl indoles

JS Yadav, BVS Reddy, AD Krishna, T Swamy

Index: Yadav; Reddy; Krishna; Swamy Tetrahedron Letters, 2003 , vol. 44, # 32 p. 6055 - 6058

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Citation Number: 43

Abstract

In this letter we highlight our results on the electrophilic sulfonylation of indoles with sulfonyl chlorides using a catalytic amount of indium bromide. Thus treatment of indole 1 (R=H) with phenylsulfonyl chloride 2 (Ar=Ph) in the presence of 10% InBr 3 in 1,2-dichloroethane afforded 3-phenylsulfonyl-1H-indole 3b in 87% yield (Scheme 1). ... A variety of indoles reacted smoothly with sulfonyl chlorides under similar conditions to give the corresponding 3-arylsulfonyl ...