ChemInform Abstract: Competitive and Selective Csp³—Br versus Csp²—Br Bond Activation in Palladium‐Catalyzed Suzuki Cross‐Coupling: An Experimental and Theoretical Study of the Role of Phosphine Ligands.

Abstract

Experimental and Theoretical Study of the Role of Phosphine Ligands. -Phosphine ligands are shown to control the selectivity in the Suzuki-Miyaura coupling of dibromo sulfoxide (I). While unhindered phosphines such as PPh3 or Xantphos selectively cause arylation of the sp 3 -hybridized, aromatic carbon [→ (III)], hindered phosphine ligands such as P(o-tolyl) 3 or P(1-naphthyl)3 reverse the selectivity in favor of the sp 2 -hybridized carbon [→ (IV)]. Identical trends are observed in external competition experiments. DFT and DFT/MM calculations show that the reactivity depends on the facility of the ligands to dissociate. -(MOLLAR, C.; BESORA, M.; MASERAS, F.; ASENSIO*, G.; MEDIO-SIMON, M.; Chem. Eur. J. 16 (2010) 45, 13390-13397, http://dx.