title: Discriminating role of bases in diketonate copper(I)-catalyzed C-O couplings: phenol versus diarylether.
abstract: The mechanism of the formation of phenol from PhI and CsOH catalysed by copper(i) ligated to the 1,3-diketonate ket'(-) generated from 2,2,6,6-tetramethyl-3,5-heptanedione (TMHD) has been investigated by DFT calculations associated with experimental techniques: cyclic voltammetry, (1)H NMR, and ESI-MS. Weak halogen bonding between the negatively charged O atom of [(ket')Cu(I)-OH](-) and PhI leads to an oxidative addition that gives (ket')Cu(III)(Ph)-OH. The latter undergoes a faster reductive elimination that delivers (ket')Cu(I)(PhOH) from which PhOH is released. PhOPh is formed in the presence of an extra base Cs2CO3. The two catalytic cycles of formation of PhOH or PhOPh are branched at the level of (ket')Cu(I)(PhOH) that can either afford PhOH in the presence of CsOH or be deprotonated by Cs2CO3 to generate [(ket')Cu(I)-OPh](-). The oxidative addition of [(ket')Cu(I)-OPh](-) to PhI leads to (ket')Cu(III)(Ph)-OPh involved in a faster reductive elimination that delivers PhOPh and the Cu(I) catalyst.
authors: Ecole Normale Supérieure, Département de Chimie, UMR CNRS-ENS-UPMC 8640, 24 rue Lhomond, F-75231 Paris Cedex 5, France.
authors: Guillaume
authors: G
authors: Lefèvre
authors: Anis
authors: A
authors: Tlili
authors: Marc
authors: M
authors: Taillefer
authors: Carlo
authors: C
authors: Adamo
authors: Ilaria
authors: I
authors: Ciofini
authors: Anny
authors: A
authors: Jutand