Synthesis of β-hydroxy sulfones via opening of hydrophilic epoxides with zinc sulfinates in aqueous media
作者:Nataliya Chumachenko、Paul Sampson
DOI:10.1016/j.tet.2006.02.043
日期:2006.5
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.
β-Acyloxysulfonyl Tethers for Intramolecular Diels−Alder Cycloaddition Reactions
作者:Nataliya Chumachenko、Paul Sampson、Allen D. Hunter、Matthias Zeller
DOI:10.1021/ol050930t
日期:2005.7.1
[reaction: see text]. beta-Hydroxy sulfone-based tethers were employed for the first time to achieve thermally mediated intramolecularDiels-Alder cycloaddition. The reactions proceeded with complete regioselectivity and high (10/1) to complete endo/exo-selectivity and resulted in the preferential formation of one of the two possible endo-cycloadducts. The yields and stereoselectivities were proportional