Tris(3,6-di-t-butyl-1-azulenyl)methyl cation; hydrocarbon cation with the highest pKR+ value
作者:Shunji Ito、Noboru Morita、Toyonobu Asao
DOI:10.1016/s0040-4039(00)75808-4
日期:1994.1
Tris(3,6-di-t-butyl-1-azulenyl)methyl (5), tri(3-t-butyl-1-azulenyl)methyl (10), and tri(6-t-butyl-1-azulenyl)methyl (11) hexafluorophosphates were synthesized. Their pKR+ values were determined as 14.3, 13.2, and 13.7, respectively, and the value of 5 showed the highest one as carbocation ever reported. The extreme stability of methyl cation 5 is mainly attributable to steric effects of six bulky
三(3,6-二-吨-丁基-1-薁)甲基(5),三(3-吨丁基-1-薁)甲基(10),和三(6-吨丁基-1-薁合成了(11)甲基六氟磷酸酯。他们的p K R +值分别确定为14.3、13.2和13.7,而5的值显示出有史以来最高的碳正离子化值。甲基阳离子5的极度稳定性主要归因于六个庞大的叔丁基的空间效应,以及三个a环的偶极结构的贡献。