Department of Chemistry, Georgetown University, Box 571227-1227, Washington, D.C. 20057, USA.
J Am Chem Soc. 2012 Oct 24;134(42):17350-3. doi: 10.1021/ja3053688. Epub 2012 Oct 16.
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) (4) and the square planar Cu(III)(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.
铜（I）β-二酮腙[Cl(2)NN]Cu([Cu(I)])与(t)BuOO(t)Bu反应的动力学分析表明，各组分均表现出一级反应行为，这意味着游离(t)BuO(•)自由基的形成。加入吡啶后，该反应受到轻微抑制，表明在过氧化物活化之前，(t)BuOO(t)Bu 和 py 之间存在竞争，争夺[Cu(I)]的配位。[Cu(I)]与二枯基过氧化物反应生成[Cu(II)]-OCMe(2)Ph(3)和苯乙酮，这表明 PhMe(2)CO(•)自由基的存在。计算方法为[Cu(I)]活化(t)BuOO(t)Bu 提供了深入的了解。新型过氧化物加合物Cu(I)(4)和平面正方形[Cu(III)] (O(t)Bu)(2)(5)被鉴定出来，它们都不稳定，容易失去(t)BuO(•)自由基。在室温下，利用[Cu(I)]（5 mol%）催化环己烷与(t)BuOO(t)Bu 的 C-H 醚化反应，可轻松生成(t)BuO(•)自由基，产物环己基醚 Cy-O(t)Bu 的收率为 60%。
