The kinetic impact of vinylic fluorine substituents on 5-hexenyl radical cyclizations
作者:William R. Dolbier、Xiao X. Rong
DOI:10.1016/0040-4039(96)01120-3
日期:1996.7
A study of the effect of vinylic fluorine substituents on the 5-hexenyl radical cyclization indicates that substituents at the 6-position, or vicinal 5,6-difluoro substitution have little effect on the rate, whereas a 5-fluoro substituent slows down the rate by a factor of 10.8, and 5,6,6-trifluoro substitution enhances the rate by a factor of 2.3. The results are explained in terms of a combination
对乙烯基氟取代基对5-己烯基自由基环化的影响的研究表明,在6位或附近的5,6-二氟取代基对速率的影响很小,而5-氟取代基会减慢速率速率提高了10.8倍,而5,6,6-三氟取代提高了速率2.3倍。根据空间效应和焓效应的组合来解释结果,并可能在三氟乙烯基的情况下干预极性影响。