Synthesis of 5-methylidenehexahydropyrrolo[l,2-a]imidazoles and 6-methylideneoctahydropyrrolo[l,2-a]pyrimidines by the reaction of 1-alkynyl-1-chlorocyclopropanes with lithium derivatives of 1,2- and 1,3-diaminoalkanes
作者:K. N. Shavrin、V. D. Gvozdev、O. M. Nefedov
DOI:10.1007/s11172-010-0261-6
日期:2010.7
A reaction of 1-alkynyl-1-chlorocyclopropanes with excess of lithium derivative of 1,2-diaminoethane leads to 5-methylidenehexahydropyrrolo[l,2-a]imidazoles in 35–72% yields, whereas analogous reaction with lithium derivative of 1,3-diaminopropane gives 6-methyl-ideneoctahydropyrrolo[l,2-a]pyrimidine in up to 50% yield. A mechanism of these unusual multi-step processes includes dehydrochlorination
1-炔基-1-氯环丙烷与过量的 1,2-二氨基乙烷锂衍生物反应生成 5-亚甲基六氢吡咯并[l,2-a]咪唑,产率为 35-72%,而与 1 的锂衍生物的类似反应, 3-二氨基丙烷以高达 50% 的产率得到 6-甲基-亚十氢吡咯并[1,2-a]嘧啶。这些不寻常的多步骤过程的机制包括 1-炔基-1-氯环丙烷脱氯化氢形成共轭炔基环丙烯,能够在双键上加成单烷基酰胺离子,产生相应的仲环丙胺;后者在反应条件下异构化为线性亚胺,其进一步经历级联环化,依次参与 C=N 和 C≡C 键。