Liquid-phase photofluorination with elemental fluorine. Part III. Synthesis of perfluorocycloalkyl ethers with/without a chlorine substituent

Abstract

Liquid-phase photofluorination (LPPF) of 2-phenyl-2-methoxyhexafluoropropane 1 gave the desired F-2-cyclohexyl-2-methoxypropane, 2, in 21% yield. An unusual rearranged product, F-2-cyclohexylmethyl isopropyl ether, 4, and a degradation product, F-2-cyclohexylpropane, 3, were also produced in 10 and 20% yields, respectively. A plausible reaction mechanism for the formation of the rearranged product 4 was presented. The Cl-containing ethers with cyclic structures, 2-chlorohexafluorocyclopentenyl cyclopentyl ether, and 2-chlorohexafluorocyclopentenyl 2,2,3,3,4,4,5,5-octafluoro- n-pentyl ether were also perfluorinated by the LPPF method to give the corresponding Cl-containing F-ethers in fair yields. The total retention of the chlorine atom through perfluorination and the ability to have a benzene substituent on the substrate are benificial features of this novel perfluorinating method.