Cyclic sulfones from double conjugate addition of Rongalite

Cyclic sulfones are obtained in up to 92% yield by double conjugate addition of Rongalite (sodium hydroxymethyl sulfinate) to dienones. The major product in each case is the kinetic <i>trans</i>-isomer of the 3,5-disubstituted ketosulfone. Eleven examples, including aryl and alkyl substituted substrates, are reported. The advantages of the method are its experimental simplicity, tolerance for both protic and oxidation-sensitive functional groups, and sterically challenging substrates. The work also significantly expands the scope of Rongalite as a conjugate nucleophile.

环砜可通过甲醛合次硫酸氢钠（Rongalite，sodium hydroxymethyl sulfinate）与二烯酮的双共轭加成反应制备，产率最高可达92%。每一例反应的主要产物均为3,5-二取代酮砜的动力学反式异构体。本研究共报道11个反应实例，涵盖芳基取代与烷基取代的底物。该方法具备如下优势：实验操作简便，对质子性官能团与氧化敏感官能团均具有良好耐受性，且可兼容空间位阻较大的底物。本研究同时大幅拓展了甲醛合次硫酸氢钠作为共轭亲核试剂的应用范围。