SYNTHESIS OF CYCLIC ETHERS WITH FLUORINATED SIDE-CHAINS

Di-tert-butyl peroxide initiated free radical addition of THF to vario us fluorinated alkenes (CF2=CH2, CF2=CFH, CH2=CHCF3, CF2=CFCF3, CF2=CF C5F11, CF2=CFOCF2CF(CF3)OCF2CF2SO2F) gives either bidirectional additi on products [CH2CH2CH2OCH(CF2CH3) (1), CH2CH2CH2OCH(CH2CHF2) (2), CH2C H2CH2OCH(CF2CH2F) (3), and CH2CH2CH2OCH(CFHCHF2) (4)] or unidirectiona l products [CH2CH2CH2OCH(CH2CH2CF3) (5), CH2CH2CH2OCH(CF2CHFCF3) (6), CH2CH2CH2OCH(CF2CHFC5F11) (7), and CH2CH2CH2OCH(CF2CHFOCF2CF(CF3)OCF2C F2SO2F) (8)] depending on the structure of the alkene. Reaction of dio xane with CF2=CFOCF2CF(CF3)OCF2CF2SO2F gives a single product, CH2OCH2 CH2OCH(CF2CHFOCF2CF(CF3)OCF2CF2SO2F) (9). In the case of hexafluoropro pene or perfluoroallylbenzene, reaction with an excess of tetrahydrofu ran gives only the monosubstituted products CH2CH2CH2OCH(CF2CHFCF3) (6 ) and CH2CH2CH2OCH(CF2CFHCF2C6F5) (11) respectively. When tetrahydrofu ran is reacted with a 3:1 molar excess of the same two perfluoroalkene s, the disubstituted products CH2CH2CH(CF2CHFCF3)OCH(CF2CHFCF3) (10) a nd CH2CH2CH(CF2CFHCF2C6F5)OCH(CF2CFHCF2C6F5) (12) are formed respectiv ely. When 18-crown-6 is reacted in the same way with fluoroalkenes in a 1:1 molar ratio, the monosubstituted products 18-crown-6-CH2CH2CF3 ( 13), 18-crown-6-CF2CHFCF3 (14), 18-crown-6-CF2CFHCF2C6F5 (15), and 18- crown-6-CF2CHFOCF2CF(CF3)OCF2CF2SO2F (16) are obtained. Polyfluorinate d 18-crown-6 products containing three and two polyfluroalkyl/aryl gro ups are prepared when 18-crown-6 is reacted with a 3:1 molar excess of perfluoropropene and perfluoroallylbenzene to give 18-crown-6-(CF2CHF CF3)(3) (17) and 18-crown-6-(CF2CFHCF2C6F5)(2) (18), respectively. (Pe ntafluorophenoxy)trimethylsilane reacts with 11 in the presence of a c atalytic amount of cesium fluoride to give compound 19, CH2CH2CH2OCH(C F2CFHCF2C6F4OC6F5). Two molecules of 11 are bridged by reaction with M e(3)SiOCH(2)CF(2)CF(2)CF(2)CH(2)OSiM(3) to give HCF2C6F4OCH2CF2CF2CF2C H2OC6F4CF2CHFCF2CHOCH2CH2CH2 (20), while 12 forms the macroheterocycle H2CH2CHCF2CFHCF2C6F4OCH2CF2CF2CF2CH2OC6F4CF2CFHCF2 (21) under similar reaction conditions. The lanthanum triflate complexes of 18-crown-6 ( 22) and 18-crown-6(CF2CFHCF3) (23) were prepared and the structures we re obtained via single-crystal X-ray analysis. Although crystals suita ble for single-crystal X-ray analysis could not be formed, lanthanum t riflate complexes were formed with polyfluorinated ethers 15 and 16 to give the fluorinated complexes La(OSO2CF3)(3)(18-crown-6-CF2CFHCF2C6F 5)(H2O) (24) and CH2CHCF2CFHOCF2C(CF3)FOCF2CF2SO2F](3+)[CF3SO3-](3) (2 5) respectively. The acid salt La[N(SO2CF3)(2)](3) (26) was also prepa red and characterized, and reacted with dibenzo-18-crown-6 to give the complex dibenzo-18-crown-6-La[N(SO2CF3)(2)](3) (27).