A facile synthesis of dimethyl 4-(α-furyl)- and 4-(α-thienyl)-6-perfluoroalkylisophthalates via acyclic precursors

Article abstract of DOI:10.1016/S0022-1139(96)03561-0

In the presence of K₂CO₃, reaction of methyl propynoate 2 with (α-furoyl)methyltriphenylphosphonium bromide 1a or (α-thienacyl)-methyltriphenylphosphonium bromide 1b gave methyl 4-(α-furoyl)-2-(triphenylphosphoranylidene)but-3-enoate 4a or methyl 4-(α-thienacyl)-2-(triphenylphosphoranylidene)but-3-enoate 4b as the major product. Phosphorane 4a or 4b could react further with methyl perfluoroalkynoates 5a-b to afford dimethyl 2-(α-furoyl-1-perfluoroalkylvinyl)-4-(triphenylphosphoranylidene)pent-2-enedioates 7a-b or dimethyl 2-(α-thienacyl-1-perfluoroalkylvinyl)-4-(triphenylphosphoranylidene)pent-2-enedioates 7c-d, respectively. Dimethyl 4-(α-furyl)-6-perfluoroalkylisophthalates 8a-b or dimethyl 4-(α-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 compounds were confirmed by IR spectroscopy, mass spectrometry, ¹H, ¹⁹F and ¹³C NMR spectra, and elemental analyses. Reaction mechanisms of the formation of compounds 4, 6, 7 and 8 were also proposed. Elsevier Science S.A.