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

Study on Fluoroalkylation and Fluoroalkoxylation 19.Iridium(Ⅰ)-Catalyzed Reaction of Fluoroalkyl Iodides with Alkenes and Alkynes

在羰基-三(三苯基膦)氢化铱(Ⅰ)催化下,氟烷基碘1与烯烃2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1也可与炔烃4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.

Polyfluoroalkyl iodides(1)reacted with alkenes 1 in the presence of hydrido-carbonyltris(triphenylphosphine)iridium(Ⅰ)to give the corresponding adducts inexcellent yields under mild conditions.1 also reacted with alkynes 4 to afford E isomerof adducts predominantly.Addition of free radical inhibitor or single electron transferscavenger to the reaction mixture partially suppressed the reaction.Diallyl ethercould be used to trap the fluoroalkyl radical to afford tetrahydrofuran derivative.XPSshowed that the valence of Ir(Ⅰ)increased at the end of the reaction.All findings seemedto indicate that the reaction involved a free radical chain mechanism initiated by Ir(I).