M60 1 QD N-Phenylsydnone reacts with perfluoropropadiene to give 3-fluoro-1 -phenyl-4-trifluoromethylpyrazole (2), anionotropic rearrangement following the dipolar cycloaddition ; with perfluoropropyne, giving a 1 : 2 mixture of (2) and the isomeric 4-fluoro-1 -phenyl-3-trifluoromethylpyrazole (3) ; and with perfluorobut-2-yne to give the homologue 1 -phenyl-3,4-bis(trifluoromethyl)pyrazole (4). Phenyl a i d e and perfluoropropadiene react at 50 'C to give a 9 : 1 mixture of 4-fluoro-1 -phenyl-5-trifluoromethyl-l,2,3-triazole (5) and 5-fluoro-1 -phenyl-4trifluoromethyl-l,2,3-triazole (6), also by consecutive cycloaddition and anionotropic rearrangement. The minor isomer, believed to be compound (6), was the only adduct isolated by similar treatment of perfluoropropyne.Perfluoropropadiene and pentafluorophenyl azide react slowly to give a low yield of an adduct believed to be 4(or 5) -fluoro-1 -pentafluorophenyl-5(or 4)-trifluoromethyl-l,2,3-triazole. The orientations of these additions are discussed in terms of the frontier orbitals involved.
The nitrones PhCH=N(R)O (R = Me, Et, PhCH2, and Ph) react rapidly with perfluoropropadiene to give the corresponding 2-R -4-difluoromethylene-5,5-difluoro-3-phenylisoxazolidines in good yield, although these isoxazolidines are unstable and decompose during catalytic hydrogenation. Perfluoropropadiene also reacts with diazophenylmethane and diazodiphenylmethane, giving 4-difluoromethylene-3,3difluoro-5-phenyl-and 5,5-diphenyl-A1 -pyrazolines. The diphenylpyrazoline decomposes on distillation giving 3-difluoromethylene-2,2-difluorodiphenylcyclopropane. The regiospecificity of these dipolar cycloadditions is discussed in relation to frontier orbital theory. Benzoyldiazophenylmethane decomposes during a slow reaction with perfluoropropadiene and the only adduct isolated is 3-difluoromethylene-2,2difluoro-4,5-diphenyIdihydrofuran. Diazodiphenylmethane reacts with perfluoropropyne to give a 1 : 1 adduct believed to be 5-fluoro-3,3-diphenyI-4-trifluoromethyl-3H-pyrazole.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.