title: Reaction of Cu(I) with dialkyl peroxides: Cu(II)-alkoxides, alkoxy radicals, and catalytic C-H etherification.
abstract: Kinetic analysis of the reaction of the copper(I) β-diketiminate [Cl(2)NN]Cu ([Cu(I)]) with (t)BuOO(t)Bu to give [Cu(II)]-O(t)Bu (1) reveals first-order behavior in each component implicating the formation of free (t)BuO(•) radicals. Added pyridine mildly inhibits this reaction indicating competition between (t)BuOO(t)Bu and py for coordination at [Cu(I)] prior to peroxide activation. Reaction of [Cu(I)] with dicumyl peroxide leads to [Cu(II)]-OCMe(2)Ph (3) and acetophenone suggesting the intermediacy of the PhMe(2)CO(•) radical. Computational methods provide insight into the activation of (t)BuOO(t)Bu at [Cu(I)]. The novel peroxide adduct [Cu(I)]((t)BuOO(t)Bu) (4) and the square planar [Cu(III)](O(t)Bu)(2) (5) were identified, each unstable toward loss of the (t)BuO(•) radical. Facile generation of the (t)BuO(•) radical is harnessed in the catalytic C-H etherification of cyclohexane with (t)BuOO(t)Bu at rt employing [Cu(I)] (5 mol %) to give the ether Cy-O(t)Bu in 60% yield.
authors.affiliation: Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, USA.
authors.forename: Raymond T
authors.initials: RT
authors.lastname: Gephart
authors.forename: Claire L
authors.initials: CL
authors.lastname: McMullin
authors.forename: Nicholas G
authors.initials: NG
authors.lastname: Sapiezynski
authors.forename: Eun Sil
authors.initials: ES
authors.lastname: Jang
authors.forename: Mae Joanne B
authors.initials: MJ
authors.lastname: Aguila
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Cundari
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Warren
mesh_terms: D002384:Catalysis; D003300:Copper / Q000737:chemistry*; D004987:Ethers / Q000138:chemical synthesis* / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry; D015394:Molecular Structure; D009942:Organometallic Compounds / Q000138:chemical synthesis / Q000737:chemistry*; D010087:Oxides / Q000737:chemistry*; D010545:Peroxides / Q000737:chemistry*
chemical_list: D004987:Ethers; D005609:Free Radicals; D009942:Organometallic Compounds; D010087:Oxides; D010545:Peroxides; D003300:Copper