title: Lanthanide-Catalyzed Oxyfunctionalization of 1,3-Diketones, Acetoacetic Esters, And Malonates by Oxidative C-O Coupling with Malonyl Peroxides.
abstract: The lanthanide-catalyzed oxidative C-O coupling of 1,3-dicarbonyl compounds with diacyl peroxides, specifically the cyclic malonyl peroxides, has been developed. An important feature of this new reaction concerns the advantageous role of the peroxide acting both as oxidant and reagent for C-O coupling. It is shown that lanthanide salts may be used in combination with peroxides for selective oxidative transformations. The vast range of lanthanide salts (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Y) catalyzes oxidative C-O coupling much more efficiently than other used Lewis and Bronsted acids. This oxidative cross-coupling protocol furnishes mono and double C-O coupling products chemo-selectively in high yields with a broad substrate scope. The double C-O coupling products may be hydrolyzed to vicinal tricarbonyl compounds, which are otherwise cumbersome to prepare. Based on the present experimental results, a nucleophilic substitution mechanism is proposed for the C-O coupling process in which the lanthanide metal ion serves as Lewis acid to activate the enol of the 1,3-dicarbonyl substrate. The side reactions-chlorination and hydroxylation of the 1,3-dicarbonyl partners-may be minimized under proper conditions.
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , 47 Leninsky prospekt, Moscow 119991, Russian Federation.
authors.forename: Alexander O
authors.initials: AO
authors.lastname: Terent'ev
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , 47 Leninsky prospekt, Moscow 119991, Russian Federation.
authors.forename: Vera A
authors.initials: VA
authors.lastname: Vil'
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , 47 Leninsky prospekt, Moscow 119991, Russian Federation.
authors.forename: Evgenii S
authors.initials: ES
authors.lastname: Gorlov
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , 47 Leninsky prospekt, Moscow 119991, Russian Federation.
authors.forename: Gennady I
authors.initials: GI
authors.lastname: Nikishin
authors.affiliation: N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences , 47 Leninsky prospekt, Moscow 119991, Russian Federation.
authors.forename: Kasimir K
authors.initials: KK
authors.lastname: Pivnitsky
authors.affiliation: Institute of Organic Chemistry, University of Würzburg , Am Hubland, D-97074 Würzburg, Germany.|Department of Chemistry, Facundo Bueso 110, University of Puerto Rico , Rio Piedras, Puerto Rico 00931, United States.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Adam