Tris(1-naphthyl)- and tris(2-naphthyl)methyl cations: highly crowded triarylmethyl cations 1
作者:George A. Olah、Qimu Liao、J. Casanova、Robert Bau、Golam Rasul、G. K. Surya Prakash
DOI:10.1039/a804505d
日期:——
The highly hindered tris(1-naphthyl)methyl and tris(2-naphthyl)methyl cations 3 and 5 have been prepared under long lived stable ion conditions and characterized by 13C NMR spectroscopy at low temperatures. The latter can abstract hydride from cycloheptatriene to afford tris(2-naphthyl)methane 7, but the reaction of cycloheptatriene with the more crowded cation 3 failed to give the corresponding hydrocarbon
在长寿命的稳定离子条件下制备了高度受阻的三(1-萘基)甲基和三(2-萘基)甲基阳离子3,并通过低温下的13 C NMR光谱对其进行了表征。后者可以从环庚三烯中提取氢化物,得到三(2-萘基)甲烷7,但是环庚三烯与更拥挤的阳离子3的反应未能得到相应的烃。 在前一种情况下发现的主要动力学同位素效应k H / k D = 7.1±0.5支持共线性氢化物提取机理。猝灭时的离子3和5重排,得到异构体13-(1-萘基)-1,2,7,8-二苯并芴4和13-(2-萘基)-2,3,6,7-二苯并芴的混合物6,分别。