An Approach toward Azacycles Using Photochemical and Radical Cyclizations of <i>N</i>-Alkenyl Substituted 5-Thioxopyrrolidin-2-ones
作者:Albert Padwa、Martin N. Jacquez、Andreas Schmidt
DOI:10.1021/jo035127w
日期:2004.1.1
thioxaphthalimido system containing an N-cycloalkenyl group in the side chain gave rise to products derived by γ-hydrogen abstraction from the n−π* triplet excited state. The photobehavior of the related N-3-alkenyl pyrrolidine-2,5-dithione system (62) was also studied and found to give products derived from both a 2 + 2 cycloaddition (63) and hydrogen atom transfer (64). Finally, the reaction of several N-alkenyl
已经研究了一系列环状的N-烯基取代的硫代酰亚胺的光化学反应。辐照N -3-甲基丁-3-烯基-5-硫代-吡咯烷酮-2-酮(16)导致分子内[2 + 2]环加成,从而产生高应变的硫杂环丁烷17,并根据其结构确定了结构X射线分析。用四氟硼酸二甲基(甲硫基)s处理环加合物17,以良好的收率得到2,5,6,7-四氢吡咯嗪-3-酮(20)。用阮内镍进一步还原20得到5,5-二甲基六氢吡咯烷-1-酮(21)。该反应顺序证明了将2 + 2光加合物转化为吡咯烷核生物碱核心骨架的便利性。密切相关的N-丁烯基噻吩并吡咯烷酮一(22)的光化学反应以略有不同的方式进行,并以68%的收率生产了7-巯基甲基四氢吡咯烷酮3-一(24)。与上述结果相反,在侧链上含有N-环烯基的硫代邻苯二甲酰亚胺基体系的辐照产生了由γ-氢从n-π*三重态激发态提取的产物。相关的N -3-烯基吡咯烷-2,5-二硫酮体系的光行为(62)也被研究并发现得到衍生自2