Reactions of vinyl sulfone with α-diazo-β-ketosulfone and Bestmann–Ohira reagent for the regioselective synthesis of highly functionalized pyrazoles
作者:Rahul Kumar、Deepa Nair、Irishi N.N. Namboothiri
DOI:10.1016/j.tet.2014.01.022
日期:2014.3
The 1,3-dipolar cycloaddition of diazomethylsulfone anion, generated in situ from α-diazo-β-ketosulfone, with vinyl sulfone proceeds in a regioselective manner to provide sulfonylpyrazoles. Similar reaction of diazomethylphosphonate anion, derived from Bestmann–Ohira reagent, with vinyl sulfone leads to phosphonylpyrazoles. The sulfonyl group of vinyl sulfone undergoes chemoselective elimination in
由α-重氮-β-酮砜与乙烯基砜原位生成的重氮甲基砜阴离子的1,3-偶极环加成反应以区域选择性的方式进行,以提供磺酰基吡唑。由Bestmann-Ohira试剂衍生的重氮甲基膦酸根阴离子与乙烯基砜的类似反应会生成膦酰基吡唑。在这些反应中,乙烯基砜的磺酰基经历化学选择性消除。