氟烷基化和氟烷氧基化的研究19: 铱(I)催化下氟烷基碘与烯烃、炔烃的加成反应

在羰基-三(三苯基膦)氢化铱(I)催化下, 氟烷基碘与烯烃加成得到高产率的加成产物, 反应条件温和, 有良好的选择性. 氟烷基碘也可与炔烃反应, 生成以E式异构体占优势的氟烷基化烯烃. 反应体系中加入自由基抑制剂或单电子转移阻止剂则大大减慢反应; 二烯丙基醚可以捕获自由基生成四氢呋喃衍生物; 光电子能谱表明部分一价铱在反应后价态升高, 这些事实表明反应为单电子转移引发下的自由基链式机理.

Study on fluoroalkylation and fluoroalkoxylation 19: Iridium(I)-catalyzed reaction of fluoroalkyl iodides with alkenes and alkynes

Polyfluoroalkyl iodides RI [I, R = Cl(CF2)4, Cl(CF2)6, CF3(CF2)3] reacted with alkenes in the presence of hydridocarbonyltris(triphenylphosphine)iridium (I) to give the corresponding adducts in excellent yields under mild conditions, I also reacted with alkynes to afford E isomer of adducts predominantly. Addition of free radical inhibitor or single electron transfer scavenger to the reaction mixture partially suppressed the reaction. Diallyl ether could be used to trap the fluoroalkyl radical to afford THF derivative XPS showed that the valence of Ir(I) increased at the end of the reaction. All findings seemed to indicate that the reaction involved a free radical chain mechanism initiated by Ir(I).