O-Cinnamyl and O-(2-methylthioethyl) S-methyl dithiocarbonates (xanthates) underwent thione-thiol rearrangement to the dithiol esters in various solvents. The reactions followed first-order kinetics and the rates were affected by change of the solvent polarity. Plots of the rate constants against the Y values showed good linear relationships. The rate constants may be used as a new empirical parameter of solvent polarity in place of Y values. Modified intermediate neglect of differential overlap (MINDO/3) calculations indicate that allylic xanthates undergo [3, 3]-sigmatropic rearrangement via a polarizable transition state.
O-肉桂基和O-(2-甲
硫基乙基) S-甲基二
硫代
碳酸酯(黄原酸盐)在各种溶剂中发生
硫醇-
硫醚重排反应,生成二
硫醇酯。反应遵循一级动力学,速率受溶剂极性变化的影响。速率常数与Y值的曲线图显示出良好的线性关系。速率常数可作为溶剂极性的新经验参数,代替Y值。修改后的中间体忽略差分重叠(MINDO/3)计算表明,烯丙基黄原酸盐通过可极化过渡态发生[3,3]-顺式重排。