Partially fluorinated heterocyclic compounds. Part 15 [1]. Further preparations of furan derivatives from pentafluorophenyl- and 1,3,4,5,6,7,8-heptafluoro-2-naphthyl prop-2-ynyl ethers. The isolation of the claisen rearrangement intermediate 1,3,4,5,6,7,8-heptafluoro-1-(propa-1,2-dienyl)-naphthalen-2-one

1,3,4,5,6,7,8-Heptafluoro-2-naphthyl prop-2-ynyl ether (5) and boiling isopropylbenzene gives 1,3,4,5,6,7,8-heptafluoro-1-(propa-1,2-dienyl)naphthalen-2-one (9) and two isomeric 2-(isopropylbenzyl)-4,5,6,7,8,9-hexafluoronaphtho 2,1-b]furans (11). Di-(4,5,6,7,8,9-hexafluoronaphtho 2,1-b]furan-2-ylmethyl) ether (17) and bis-(4,5,6,7,8,9-hexafluoronaphtho 2,1-b]furan-2-y1)methane (18) are formed from (5) in CF₂ClCFCl₂ at 137°. The solvolysis of 2-fluoromethyl-4,5,6,7,8,9-hexafluoronaphtho-2,1-b]furan (10) in water at 145–156° yields (17) (2%), (18) (37%) and 4,5,6,7,8,9-hexafluoronaphtho2,1-b]furan-2-ylmethyl alcohol (19) (13%). Pentafluorophenyl prop-2-ynyl ether (1) reacts in either C₆F₆ or CF₂ClCFCl₂ at 140° to give di-(4,5,6,7-tetrafluorobenzo b] furan-2-ylmethyl) ether (15). The major product from the solvolysis of 2-fluoromethyl-4,5,6,7-tetra-fluorobenzo b] furan (2) in water at 140–142° is 4,5,6,7-tetra-fluorobenzo b] furan-2-ylmethyl alcohol (16) (87%) accompanied by (15) (2.5%).