A FACILE SYNTHESIS OF DIMETHYL 4-(ALPHA-FURYL)-6-PERFLUOROALKYLISOPHTHALATES AND 4-(ALPHA-THIENYL)-6-PERFLUOROALKYLISOPHTHALATES VIA ACYCLIC PRECURSORS

In the presence of K2CO3, reaction of methyl propynoate 2 with (alpha- furoyl)methyltriphenylphosphorium bromide la or (alpha-thienacyl)methy ltriphenylphosphonium bromide Ib gave methyl furoyl)-2-(triphenylphosp horanylidene)but-3-enoate 4a or methyl enacyl)-2-(triphenylphosphorany lidene)but-3-enoate 4b as the major product. Phosphorane 4a or 4b coul d react further with methyl perfluoroalkynoates 5a-b to afford dimethy l l)-4-(triphenylphosphoranylidene)pent-2-enedioates 7a-b or dimethyl l)-4-(triphenylphosphoranylidene)pent-2-enedioates 7c-d, respectively. Dimethyl 4-(alpha-furyl)-6-perfluoroalkylisophthalates 8a-b or dimeth yl 4-(alpha-thienyl) -6-perfluoroalkylisophthalates 8c-d were prepared in high yields via intramolecular Wittig reaction of phosphoranes 7a- d under heating in a sealed tube in xylenes. The structures of these c ompounds were confirmed by IR spectroscopy, mass spectrometry, H-1, F- 19 and C-13 NMR spectra, and elemental analyses. Reaction mechanisms o f the formation of compounds 4, 6, 7 and 8 were also proposed. (C) Els evier Science S.A.