title: Synthesis, characterization, and unique catalytic activities of a fluorinated nickel enolate.
abstract: We have synthesized a new nickel enolate [(PhCOCF2)Ni(dcpe)][FB(C6F5)3] featuring fluorine atoms on the enolate moiety via B(C6F5)3-promoted C-F bond activation of α,α,α-trifluoroacetophenone. X-ray diffraction study of [(PhCOCF2)Ni(dcpe)][FB(C6F5)3] revealed that the complex had adopted an η(3)-oxallyl coordination mode in the crystal lattice. The reaction of (t)BuNC with [(PhCOCF2)Ni(dcpe)][FB(C6F5)3] resulted in the coordination of isocyanide to the nickel center to form a C-bound enolate complex. The reactions of [(PhCOCF2)Ni(dcpe)][FB(C6F5)3] with aldehydes gave insertion products quantitatively which were fully characterized by NMR spectroscopy. Furthermore, we established unique catalytic applications for [(PhCOCF2)Ni(dcpe)][FB(C6F5)3] toward a Tishchenko reaction, along with a highly selective crossed-esterification of α,α,α-trifluoroacetophenones with aldehydes.
authors.affiliation: Department of Applied Chemistry, Faculty of Engineering, Osaka University , Suita, Osaka 565-0871, Japan.
authors.forename: Ryohei
authors.initials: R
authors.lastname: Doi
authors.forename: Kotaro
authors.initials: K
authors.lastname: Kikushima
authors.forename: Masato
authors.initials: M
authors.lastname: Ohashi
authors.forename: Sensuke
authors.initials: S
authors.lastname: Ogoshi