compounds whereas in the presence of added propionic anhydride the thio-ester was obtained. Under these latter conditions (R = C5H11CH(OSiX)CC-) rearranged to give a mixture of and whereas in DME containing CH3COOH-H2O (trace) the desired 2,3-disubstituted 4-piperidones and were obtained in 95 % combined yield.
由(Lawesson试剂,85%)制备的
硫代
哌啶酮与烯丙基
溴进行快速反应,得到5,6-
二氢吡啶鎓盐。通过与适当的
格氏试剂反应,得到C-2官能化的中间体。在
DME中于120℃加热(R = Pr)导致形成环化化合物,而在添加
丙酸酐的存在下获得
硫代酯。在这些后者的条件下(R = C 5 H ^ 11 CH(OSIX)CC-)重排,得到的混合物,并在
DME含有CH而3 COOH-H 2O(痕量)所需的2,3-二取代的
4-哌啶酮,以95%的合并产率获得。