A novel route to sulphonium ylides, which consists in condensation of sulphoxides with active methylene compounds, gives stable, crystalline products I–XIII listed in Tables 1 and 2. NMR spectra of these ylides (Figs. 1–4) show remarkable temperature-dependence, the implications of which with respect to conformational equilibria have been discussed. Steric and electronic effects of aromatic Me groups
一种新的制备的方法,该方法包括亚砜与活性亚甲基化合物的缩合,生成表1和表2中列出的稳定的结晶产物I–XIII。这些耶德的NMR光谱(图1-4)显示出显着的温度依赖性。 ,已经讨论了其对于构象平衡的含义。NMR光谱证明,甲基磺酰甲基XVI的芳族Me基团的立体和电子效应导致平衡的XVIA⇌XVIB。酰基XVII和XVIII中
硫原子的
金字塔结构由与
硫原子连接的两个亚甲基的质子不等价指示(图6和7)。已经制备了几种新颖的苯并sulph酰
苯胺(表3),并且将这些成对的对进行交换。