the ortho position is described. These compounds undergo iminium ion mediated cyclization when treated with titanium tetrachloride or gaseous hydrogen chloride. Mechanistically, cyclization utilizes attack of C-3 of the dihydropyridine on the electrophilic species generated from complexation of the acetal. This methodology highlights opportunities for the construction of novel conformationally constrained
描述了在邻位具有保护的醛官能度的4-芳基-1,4-
二氢吡啶的合成。当用
四氯化钛或气态
氯化氢处理时,这些化合物会经历
亚胺离子介导的环化反应。从机理上讲,环化利用
二氢吡啶的C-3对
缩醛络合产生的亲电子物质的攻击。该方法论突出了构建新型构象受限的
二氢吡啶类似物的机会。