M.C. White, Chem 153 Nu attack on olefins -328 Week of November 25, 2002 Wacker oxidation CuCh(cat) 2 mechanistic possibilities for hydroxypalladation HO. HCI The Wacker oxidation is used H,O nOH习y industrially to produce -4 million tons of acetaldehyde/year CI H0 1n2 O 2 CuCI H,0 2 CuCh Deuterium labeling study indicates that hydroxypalladation proceeds Ln Pd(o) via palladium-nucleophile anti-addition HCl H,0 H LmPd OH H,O 阝 hydride elimination HO merical production of hyde OH Binding specificity: terminal olefins Regioselectivity: 2 carbon Remote functionality tolerated Stille JOMC 1979(169)239M.C. White, Chem 153 Nu attack on Olefins -328- Week of November 25, 2002 2 mechanistic possibilities for hydroxypalladation: Cl Pd H2O II OH R syn hydroxypalladation Cl PdII H2O OH R Cl Pd H2O Cl II R anti hydroxypalladation OH2 Cl Pd H2O II Cl OH R Deuterium labeling study indicates that hydroxypalladation proceeds via palladium-nucleophile anti-addition. LnPdII H D D H D H LnPdII OH H D OH2 H+ CO HD D H OH O PdII Ln O H D DH O Pd0 Ln Stille JOMC 1979 (169) 239. Wacker Oxidation H2O HCl 2 CuCl H2O 2 Cl Pd H2O II Cl OH2 Cl Pd H2O Cl II R Cl Pd H2O Cl II OH2 + R Cl Pd H2O II OH R H Cl Pd H2O H II OH R H2O Pd H2O II Cl H R R HO O R R O R HCl Commericial production of acetaldehyde β-hydride elimination LnPd(0) 2 CuCl 1/2 O2 + 2 HCl · Binding specificity: terminal olefins · Regioselectivity: 2o carbon · Remote functionality tolerated PdCl2 (cat) CuCl2 (cat) O2, H2O, HCl The Wacker oxidation is used industrially to produce ~ 4 million tons of acetaldehyde/year. hydroxypalladation