indicated that their reactivity differences can be explained by an influence of steric hindrance in the considered transition state. In result, the synthesis of the 3-acetyl-1-methylthiocycloalka[c]pyridines, as synthons for preparation of sempervirine and its analogues has been optimized. The subsequent side reaction has been detected as a serious problem, especially in the case of the six-membered
5-乙酰基-3-甲
硫基
1,2,4-三嗪与五个环烯胺的狄尔斯-阿尔德反应已在制备和理论方面进行了重新研究。它的区域选择性已经在实践中得到发展,这与FMO相互作用(包括过渡态的次级轨道相互作用)的理论考虑是一致的。由于对所有五对能量的需求都相似,因此已经表明,它们的反应性差异可以通过所考虑的过渡态中的空间位阻的影响来解释。结果,合成了3-乙酰基-1-甲基
硫代环烷基[ c作为制备sempervirine及其类似物的合成子的
吡啶已得到优化。已检测到随后的副反应是一个严重的问题,尤其是在六元烯胺的情况下,其与反应混合物中形成的最终产物的乙酰基反应。