Electrophilic activation and reactivity control of fluorinated alkenes by transition-metal complexes

我们发现，用阳离子钯（II）催化剂处理含有联苯骨架的1,1-二氟-1-烯烃（或1,1,2-三氟-1-烯烃），由氯化钯（II）和银盐生成，可以顺利地得到氟化（或二氟化）菲衍生物。在此过程中，氟化烯烃基团似乎通过π配位到Pd（II）中心而被亲电活化，从而促进了产物的friedel - crafts型环化反应。我们的催化工艺从精心设计的1,1-二氟-1-烯烃开始，完成了氟化多环芳烃（F-PAHs）的区域选择性合成。

We have found that treatment of 1,1-difluoro-1-alkenes (or 1,1,2-trifluoro-1-alkenes) bearing a biphenyl skeleton with cationic Pd(II) catalysts, generated from palladium(II) chloride and silver salts, smoothly affords fluorinated (or difluorinated) phenanthrene derivatives. In this process, the fluorinated alkene moieties seem to be electrophilically activated through π coordination to Pd(II) center, which promotes Friedel-Crafts-type cyclizations to give the products.Regioselective syntheses of fluorinated polycyclic aromatic hydrocarbons (F-PAHs) have been accomplished by our catalytic process starting from well-designed 1,1-difluoro-1-alkenes.