Nickel-Catalyzed, Directing-Group-Assisted [2+2+2] Cycloaddition of Imine and Alkynes
作者:Laksmikanta Adak、Wei Chuen Chan、Naohiko Yoshikai
DOI:10.1002/asia.201000564
日期:2011.2.1
[2+2+2] cycloaddition reaction with two alkyne molecules under nickel catalysis to afford a 1,2‐dihydropyridine derivative in moderate to good yield. The reaction is likely to involve oxidative cyclization of the imine and alkyne, insertion of another alkyne, and CN reductive elimination, followed by a 1,5‐sigmatropic hydrogen shift. The pyridyl group is proposed to facilitate the reaction by chelation
带有3-甲基-2-吡啶基的醛亚胺在镍催化下与两个炔烃分子进行[2 + 2 + 2]环加成反应,以中等至良好的收率得到1,2-二氢吡啶衍生物。该反应可能涉及亚胺和炔,另一炔的插入,和C的氧化环化 Ñ还原消除,随后是1,5-σ迁移氢移。吡啶基被提议通过与氮杂-尼克环中间体的螯合来促进反应。