Shellhamer Dale F, Allen Jeannette L, Allen Rachel D, Gleason David C, O'Neil Schlosser Colleen, Powers Benjamin J, Probst John W, Rhodes Michelle C, Ryan Andrew J, Titterington Peter K, Vaughan Gregory Gawayne, Heasley Victor L
Department of Chemistry, Point Loma Nazarene University, San Diego, California 92106-2899, USA.
J Org Chem. 2003 May 16;68(10):3932-7. doi: 10.1021/jo030030v.
Ionic reactions of terminal alkenes with chlorine (Cl(2)), bromine (Br(2)), and iodine monochloride (ICl) are sensitive to the alkyl substituents, and the positions and number of vinyl fluorine atoms. These perturbations influence the symmetry of the halonium ion intermediates, which can be determined by the distribution of the Markovnikov to anti-Markovnikov products. A vinyl fluorine on the number-2 carbon favors an unsymmetrical intermediate with greater charge on the number-2 carbon unless the alkyl group is electron withdrawing. A vinyl fluorine on the terminal number-1 carbon favors positive charge development on that carbon unless a resonance stabilizing group is on the number-2 carbon. The symmetry of halonium ions with vinyl fluorines on both carbons-1 and -2 depends primarily on the characteristics of the alkyl substituent. Intermediates range from open-ions with the positive charge on carbon-2, to various bridged species, to open-ions on the terminal carbon.
末端烯烃与氯（Cl₂）、溴（Br₂）和一氯化碘（ICl）的离子反应对烷基取代基、乙烯基氟原子的位置和数量敏感。这些扰动会影响卤鎓离子中间体的对称性，这可以通过马氏产物与反马氏产物的分布来确定。2号碳上的乙烯基氟有利于形成不对称中间体，2号碳上电荷更多，除非烷基是吸电子的。1号末端碳上的乙烯基氟有利于该碳上正电荷的发展，除非2号碳上有共振稳定基团。碳-1和-2上都有乙烯基氟的卤鎓离子的对称性主要取决于烷基取代基的特性。中间体的范围从2号碳带正电荷的开链离子，到各种桥式物种，再到末端碳上的开链离子。
