PREPARATION OF SOME HIGHLY HALOGENATED DERIVATIVES OF FURAN

Article abstract of DOI:10.1016/S0022-1139(00)82614-7

Direct chlorination of 2-(2H-hexafluoropropyl)-tetrahydrofuran 1 gave high yield of 2-(2-chlorohexafluoropropyl)-pentachloro-2,5-dihydrofuran 2.Bromination of 1 gave very complex mixture of products, from which three compounds, viz. 2-bromo-5-(2H-hexafluoropropyl)-furan 3, 3-bromo-5-(2Hhexafluoropropyl)-furan 4, and 2,4-dibromo-5-(2H-hexafluoropropyl)-furan 5 were isolated.Exchange fluorination of 2 with dry KF at 240 - 300 deg led to a stepwise substitution of fluorines for chlorines to give mixtures of chloro-fluoro-2-(2-chlorohexafluoropropyl)-dihydrofurans 7,8,9 and 10 together with small amounts of 2-(2-chlorohexafluoropropyl)-3,4,5-trichlorofuran 6.Exchange fluorination of 3,4-dihalo-2,2,5,5-tetrafluoro-2,5-dihydrofurans 11a and 11b led to a substitution of fluorine for one vinylic halogen to give 3-halo-2,2,4,5,5-pentafluoro-2,5-dihydrofurans 12a and 12b in good yields.Compounds 2 - 12 were characterized by n.m.r., m.s., and i.r. spectroscopy and elemental analysis.