来自跳跃氮杂烯二炔的α,5-二脱氢-3-甲基吡啶双自由基：氮杂迈尔斯-斋藤环化反应的计算与捕获研究

alpha,5-didehydro-3-picoline diradicals from skipped azaenediynes: computational and trapping studies of an aza-Myers-Saito cyclization.

作者信息

Feng Liping, Kumar Dalip, Birney David M, Kerwin Sean M

机构信息

Division of Medicinal Chemistry, College of Pharmacy, The University of Texas at Austin, Austin, Texas 78712, USA.

出版信息

Org Lett. 2004 Jun 10;6(12):2059-62. doi: 10.1021/ol049266r.

DOI:10.1021/ol049266r

PMID:15176818

Abstract

[reaction: see text] On the basis of density functional calculations, the isomerization of skipped azaenediynes (C-alkynyl-N-propargylimines) to azaenyne allenes and subsequent rapid aza-Myers-Saito cyclization to alpha,5-didehydro-3-picoline were predicted. We prepared the N-propargylimine of 1-phenyl-3-tri(isopropyl)silylprop-2-yn-1-one, which undergoes proto-desilylation and isomerization to an azaenyne allene when treated with tetrabutylammonium fluoride. In the presence of 1,4-cyclohexadiene, this azaenyne allene affords 6-phenyl-3-picoline and other products corresponding to the trapping of an alpha,5-didehydro-3-picoline diradical.

摘要

[反应：见正文]基于密度泛函计算，预测了跳跃式氮杂二炔（碳炔基 - N - 炔丙基亚胺）异构化为氮杂烯炔丙二烯以及随后快速的氮杂迈尔斯 - 斋藤环化反应生成α,5 - 二脱氢 - 3 - 甲基吡啶。我们制备了1 - 苯基 - 3 - 三（异丙基）甲硅烷基丙 - 2 - 炔 - 1 - 酮的N - 炔丙基亚胺，当用四丁基氟化铵处理时，它会发生质子 - 脱硅反应并异构化为氮杂烯炔丙二烯。在1,4 - 环己二烯存在下，这种氮杂烯炔丙二烯会生成6 - 苯基 - 3 - 甲基吡啶以及其他与捕获α,5 - 二脱氢 - 3 - 甲基吡啶双自由基相对应的产物。