Thermal and microwave assisted reactions of 2,5-disubstituted thienosultines with [60]fullerene: non-Kekulé biradicals and self-sensitized oxygenation of the cycloadduct
作者:Chih-Chin Chi、I-Feng Pai、Wen-Sheng Chung
DOI:10.1016/j.tet.2004.09.040
日期:2004.11
boat-to-boat inversion of these 4′,5′,6′,7′-tetrahydrobenzo[c]thieno-[5′,6′:1,2][60]fullerene adducts 12a–f were found to be in the range of 13.5–14.8 kcal/mol. Unexpectedly, one of the monoadduct 12a was found to be labile when kept in air under ambient light. Two new products 15 (a sulfine-enone) and 16 (an endione) were isolated from the decomposed 12a and were found to derive from self-sensitized singlet
用[60]富勒烯将2,5-二取代的噻吩并合素10a - f的邻二氯苯溶液回流2-24小时,得到1:1和2:1的环加合物,分离产率为37-79%。微波辐射使反应高度加速,从而得到相当的环加合物收率。苏丹嘌呤10a - f经历了SO 2的化学挤压,形成了相应的非Kekule双自由基中间体11a - f,随后这些中间体被[60]富勒烯捕获,形成了相应的环加合物。活化能垒(ΔG c ≠)确定用于船到船反转这些4',5',6',7'-四氢苯并[ C ^ ]噻吩并[5',6':1,2] [60]富勒烯加合物12A - ˚F分别发现在13.5-14.8 kcal / mol的范围内。出乎意料的是,发现单加合物12a之一在环境光下保持在空气中时不稳定。从分解的12a中分离出两个新产物15(磺基-烯酮)和16(一个末端基),发现它们来自于12a的2,5-二甲基噻吩部分上的自敏单线态氧反应。