Preparation, X-ray Crystal Structures, and Reactivity of Alkynylcyclopropenylium Salts
作者:Robert D. Gilbertson、Timothy J. R. Weakley、Michael M. Haley
DOI:10.1021/jo9915372
日期:2000.3.1
produced only the corresponding monocations. A dication was prepared when an ethylene spacer was inserted between the acetylene groups of the butadiyne-bridged biscyclopropene. Single-crystal X-ray structures of three of the cyclopropenylium ions were obtained. pK(R+) titrations were carried out on two of the salts, which showed that acetylene substituents provide about the same degree of stability
通过炔属亲核试剂与高氯酸二苯基环丙烯基酯的反应制备了几种1,2-二苯基-3-炔基环丙烯。经由与三苯甲基阳离子的氢化物提取,将环丙烯转化为炔基环丙烯基盐。尝试由乙炔桥联或丁二炔桥联的双环丙烯制备双酚盐的尝试仅产生相应的单阳离子。当在丁二炔桥联的双环丙烯的乙炔基之间插入乙烯间隔基时,制备了指示剂。获得了三个环丙烯基离子的单晶X射线结构。对其中的两种盐进行了pK(R +)滴定,表明乙炔基取代基可为环丙烯基核心提供与苯基大致相同的稳定性。在动力学条件下将亲核性加成到炔基环丙烯基离子上得到统计上的混合物。然而,在热力学反应条件下,亲核加成之后开环仅产生三种可能产物之一。进行了从头算的计算,以确定阳离子的电荷分布。