Catalytic regioselective sulfonylation of alpha-chelatable alcohols: Scope and mechanistic insight

Martinelli MJ; Vaidyanathan R; Pawlak JM; Nayyar NK; Dhokte UP; Doecke CW; Zollars LMH; Moher ED; Van Khau V; Kosmrlj B

Journal of the American Chemical Society, Vol.124, No.14, 3578-3585, 2002

Martinelli MJ, Vaidyanathan R, Pawlak JM, Nayyar NK, Dhokte UP, Doecke CW, Zollars LMH, Moher ED, Van Khau V, Kosmrlj B

This paper describes a convenient protocol for the regioselective sulfonylation of alpha-chelatable alcohols. Typically, the reaction of alpha-heterosubstituted alcohols with 1 equiv of p-TsCl and 1 equiv of Et3N in the presence of 2 mol % of Bu2SnO leads to rapid, regioselective, and exclusive monotosylation. The pKa of the amine was correlated to the reaction rate. A plausible mechanism for this reaction has been proposed on the basis of Sn-119 NMR studies.