Intramolecular Photocycloaddition of Unsaturated Isoquinuclidines. Synthesis of 2-Azatetracyclo[4.0.0.<sup>4,9</sup>0<sup>7,10</sup>]decanes and 3-Azatetracyclo[6.1.1.0.<sup>2,7</sup>0<sup>5,9</sup>]decanes
作者:Younggi Choi、James D. White
DOI:10.1021/jo0401321
日期:2004.5.1
2-Azabicyclo[2.2.2]oct-5-enes bearing an endo alkenyl substituent were synthesized by Diels−Alder addition of methyl vinyl ketone to a 1,6-dihydropyridine derived from methyl nicotinate. Although 1,5-dienes with this skeleton were unreactive under thermal conditions, they were photochemically reactive. Irradiation of these dienes through a Corex filter resulted in intramolecular [2 + 2] cycloaddition
带有内链烯基取代基的2-Azabicyclo [2.2.2] oct-5-烯通过Diels-Alder将甲基乙烯基酮加到衍生自烟酸甲酯的1,6-二氢吡啶合成。尽管具有该骨架的1,5-二烯在热条件下不反应,但它们具有光化学反应性。这些二烯通过Corex滤光片的辐照导致分子内[2 + 2]环加成反应产生“平行”和“交叉”光加合物以及少量六氢异喹啉。后者被认为代表负责平行光加合物的双自由基中间体的泄漏。在光化学反应中形成的新的2-氮杂环戊环[4.4.0.0.4,907,10]癸烷和3-氮杂环戊环[6.1.1.0.2,705,9]癸烷结构是热稳定的。