Synthesis of β-hydroxy sulfones via opening of hydrophilic epoxides with zinc sulfinates in aqueous media

Reaction of hydrophilic epoxides (ethylene oxide and propylene oxide) with readily accessible zinc sulfinates in aqueous solution under essentially neutral conditions afforded beta-hydroxy sulfones in good yields. This method avoids the need for organic solvents and produces ZnO as the only major reaction byproduct. 2-(Methylsulfonyl)ethanol, a common reagent for the protection of various functional groups, was obtained by this methodology from ethylene oxide in 78% yield. Reaction of various simple zinc alkane- and benzenesulfinates with propylene oxide proceeded regioselectively in 63-67% yield. The corresponding opening of these epoxides with zinc 1,3-butadiene-1-sulfinate afforded 1-butadienyl beta-hydroxyalkyl sulfones in 30% yield. Mechanistic studies revealed that the yields of these products were limited by their consumption in competing intra- and intermolecular Michael addition processes. (c) 2006 Elsevier Ltd. All rights reserved.