Chaudhuri Rupsha, Liao Hsin-Yi, Liu Rai-Shung
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan, ROC.
Chemistry. 2009 Sep 7;15(35):8895-901. doi: 10.1002/chem.200900580.
Treatment of 1-aryl-1-allen-6-enes with [PPh(3)AuCl]/AgSbF(6) (5 mol %) in CH(2)Cl(2) at 25 degrees C led to intramolecular [3+2] cycloadditions, giving cis-fused dihydrobenzo[a]fluorene products efficiently and selectively. The reactions proceeded with initial formation of trans/cis mixtures of 2-alkyl-1-isopropyl-2-phenyl-1,2-dihydronaphthalene cations B, which were convertible into the desired cis-fused cycloadducts through the combined action of a gold catalyst and a Brønsted acid. Theoretic calculation supports the participation of the trans-B cation as reaction intermediate. Although HOTf showed similar activity towards several 1-aryl-1-allen-6-enes, it lacks generality for this cycloaddition reaction.
在二氯甲烷中，于25℃下用[三苯基膦金（I）氯化物]/六氟锑酸银（5 mol%）处理1-芳基-1-丙二烯-6-烯，会发生分子内[3 + 2]环加成反应，高效且选择性地生成顺式稠合的二氢苯并[a]芴产物。反应最初生成2-烷基-1-异丙基-2-苯基-1,2-二氢萘阳离子B的反式/顺式混合物，通过金催化剂和布朗斯特酸的共同作用，这些阳离子可转化为所需的顺式稠合环加成产物。理论计算支持反式-B阳离子作为反应中间体参与反应。尽管三氟甲磺酸对几种1-芳基-1-丙二烯-6-烯表现出相似的活性，但对于这种环加成反应，它缺乏通用性。
