Novel Photoreactions of 2-Aza-1,4-dienes in the Triplet Excited State and via Radical-Cation Intermediates. 2-Aza-di-π-methane Rearrangements Yielding Cyclopropylimines and<i> N</i>-Vinylaziridines
作者:Diego Armesto、Olga Caballero、Maria J. Ortiz、Antonia R. Agarrabeitia、Mar Martin-Fontecha、M. Rosario Torres
DOI:10.1021/jo034452g
日期:2003.8.1
2-aza-1,4-dienes, by using 9,10-dicyanoanthracene (DCA) as an electron-acceptor sensitizer and biphenyl as cosensitizer, brings about regioselective formation of N-vinylaziridines. Under these conditions, azadiene 1 also affords cyclopropylimine 37, resulting from an aryl-di-pi-methane rearrangement. This result demonstrates that di-pi-methane reactions can also take place via radical-cation intermediates
通过2-氮杂-di-pi-甲烷(2-ADPM)重排途径,对2-氮杂-1,4-二烯进行三重态敏化辐照可提供N-环丙基亚胺。在五苯基取代的氮杂二烯1的情况下,辐射导致形成环丙基亚胺2以及N-乙烯基氮丙啶3。该转变代表产生三元杂环产物的二-pi-甲烷重排反应的第一个实例。通过使用9,10-二氰基蒽(DCA)作为电子受体敏化剂和联苯作为共敏化剂,对2-氮杂-1,4-二烯进行SET敏化辐照,可形成N-乙烯基氮丙啶的区域选择性形成。在这些条件下,氮杂二烯1还提供了由芳基-二-pi-甲烷重排产生的环丙基亚胺37。该结果表明,二-pi-甲烷反应也可以通过自由基阳离子中间体发生。