Deux cyclopropabenzynes sont formes par debromhydratation des bromo-2 et bromo-3 norcaratrienes-1,3,5
Deux cyclopropabenzynes sont formes par debromhydration des bromo-2 et bromo-3 norcaratrienes-1,3,5
Regioselectivity and Mechanism of Dihalocarbene Addition to Benzocyclopropene
作者:Marina Khrapunovich、Ekaterina Zelenova、Lillian Seu、Alexis N. Sabo、Aidan Flaherty、Dina C. Merrer
DOI:10.1021/jo071203+
日期:2007.9.1
regioselectively to aryl-substituted benzocyclopropenes to produce dihalobenzocyclobutenes. The regioselectivity of addition is not due to steric effects but depends on the electronic donor or acceptor ability of the substituent. B3LYP/6-31G* calculations show preferential :CCl2 addition to substituted benzocyclopropene through electrophilic attack on the benzocyclopropene π-system (Ea = 1.1−2.4 kcal/mol)
二卤代卡宾向区域选择性地加成芳基取代的苯并环丙烯,以生产二卤代苯并环丁烯。加成的区域选择性不是由于空间效应,而是取决于取代基的电子给体或受体能力。B3LYP / 6-31G *计算表明:通过对苯并环丙烯π系统的亲电攻击(E a = 1.1-2.4 kcal / mol),CCl 2可优先添加到取代的苯并环丙烯中,而不是将C-Cσ键插入环丙烯基部分中(E a = 5-24 kcal / mol)。π-加成通过一个过渡态选择性地向亚二甲苯中间体或直接向苯并环丁烯产物进行。
Studies in the cycloproparene series: 2-halocyclopropabenzenes1
作者:Brian Halton、Clifford J. Randall
DOI:10.1016/s0040-4039(00)85903-1
日期:1982.1
Labelling studies show that dehydrohalogenation of the tetrahalobicycloheptane (8b,c) yields the title compounds (5a,b) both with and without skeletal rearrangement. 2-Chlorocyclopropabenzene (5b) is the major product and the expected 2-bromo derivative (5a) the minor product of reaction from the ‘mixed’ tetrahalide (8c).