The solvolytic reaction of several 9-(ortho-substituted phenylmethyl)fluoren-9-yltrimethylammonium salts has been investigated in several different solvents. Substitution and elimination products were found for the reactions in all the solvents studied, with the exceptions that reaction in both tert-butyl alcohol and chloroform led exclusively to the alkene product. The observed rate constants for alkene formation and the percent alkene were measured and it was found that the di-ortho compounds reacted at a faster rate but produced less alkene than the reaction of the corresponding mono-ortho salts. Hydrogen–deuterium isotope effects were also determined for the various reactions. The results are discussed in terms of the reaction proceeding by way of the E1 mechanism, where steric acceleration promotes the loss of the bulky ammonium leaving group to give the carbocation intermediate.
本文研究了9-(邻取代苯甲基)芴-9-基三甲基铵盐在不同溶剂中的溶化解离反应。在所研究的所有溶剂中,除了在叔丁醇和氯仿中仅生成烯烃产物外,其他溶剂中均发现了取代和消除产物。测量了烯烃形成的观察速率常数和烯烃的百分比,发现二邻位化合物反应速率较快,但产生的烯烃比相应的单邻位盐少。还确定了各种反应的氢-氘同位素效应。结果讨论了反应通过E1机制进行,其中立体加速促进了庞大铵基团的丢失,从而形成碳正离子中间体。