title: Generation of Hydrofluoronickelacycles from Trifluoroethylene and Ni(0): Ligand Effects on Regio-/Stereoselectivity and Reactivity.
abstract: Treatment of Ni(0) complexes 1a-e with sub-atmospheric pressures of trifluoroethylene (TrFE) affords hydrofluoronickelacyclopentanes L2Ni(C4F6H2) 2a-e (L = PPh3, P(O-o-tol)3, PPh2Me, PPhMe2, PMe3). Fluorine NMR analysis of 2a-e demonstrates predominant formation of three (of the possible six) isomers upon oxidative cycloaddition of TrFE: the cis and trans head-tail isomers and the trans head-head isomer, where the CHF group is defined as the TrFE "head". The respective ratios of L2Ni(C4F6H2) isomers are influenced by the nature of L, with smaller phosphines favoring the thermodynamically preferred (from DFT calculations) trans head-head isomer (cf. 50% with PMe3) and the largest affording small amounts of the tail-tail isomers. Lewis and Brønsted acids induce a surprising double C-F bond activation in 2c-d, affording small functionalized hydrofluoroalkenes. Interestingly, varying the acid employed dictates the organic product obtained from the head-tail isomers: BF3·OEt2is selective for 1,1,2,3-tetrafluorocyclobutene, whereas Me3SiOTf and N,N-dimethylanilinium bromide yield (Z,E)-1,1,3,4-tetrafluorobutadiene as the major fluorinated product. Reaction intermediates were isolated, and possible pathways are discussed.
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Kaitie A
authors.initials: KA
authors.lastname: Giffin
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Lorraine A
authors.initials: LA
authors.lastname: Pua
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Sarah
authors.initials: S
authors.lastname: Piotrkowski
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Bulat M
authors.initials: BM
authors.lastname: Gabidullin
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: Ilia
authors.initials: I
authors.lastname: Korobkov
authors.affiliation: Department of Chemistry, Dartmouth College , 6128 Burke Laboratories, Hanover, New Hampshire 03755, United States.
authors.forename: Russell P
authors.identifier: 0000-0002-1891-6530
authors.initials: RP
authors.lastname: Hughes
authors.affiliation: Department of Chemistry and Biomolecular Sciences and Centre for Catalysis Research and Innovation, University of Ottawa , 30 Marie Curie, Ottawa, Ontario K1N 6N5, Canada.
authors.forename: R Tom
authors.identifier: 0000-0002-1133-7149
authors.initials: RT
authors.lastname: Baker