New coinage metal heptafluoroisopropyl (LnM-hfip) complexes are synthesized from the metal fluoride and inexpensive hexafluoropropene [M = Ag, Cu ; L = , PPh3, 2,2,6,6-tetramethylpiperidine (Htmp)]. Reaction of the silver Htmp complex with a Ni dibromide complex leads to efficient hfip transfer to afford L2NiBr(hfip) [L = 2-ethylpyridine]. Treatment of Ni-hfip complexes with ZnPh2 gives the corresponding L2NiPh(hfip) complexes that are investigated for reductive elimination of PhCF(CF3)2. Although the desired RE proved unsuccessful, addition of carbon monoxide to L2NiPh(hfip) leads to an efficient hfip carbonylative cross-coupling. Further, while the silver complex does not undergo hfip transfer to organic electrophiles, the copper complex [(phen)(PPh3)Cu(hfip); 3b] effectively transfers the hfip unit to various substrates. We investigated the scope of 3b with acid chlorides toward the synthesis of perfluoroisopropyl aryl ketones. Additionally, new routes to 3-(4-fluorophenyl)-2-trifluoromethyl-2,1,1,1-trifluoropropane and heptafluoro-1-methylethyl-(4-fluoro-phenyl)carbinol are established. As an added bonus, 3b is easily generated on a gram scale using commercially available copper hydride by taking advantage of a rapid hydrodefluorination to generate “Cu-F” in situ. Aspects of the observed reactivity are supported by DFT calculations.

From ceiling to fluorine: Stable metal heptafluoroisopropyl complexes and transfer reagents

255th National Meeting (2018)

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