The Wacker Oxidation is an industrial process, which allows the synthesis of ethanal from ethene by palladium-catalyzed oxidation with oxygen. Copper serves as redox cocatalyst.
The lab scale modification - the Wacker-Tsuji Oxidation - is useful for the synthesis of various ketones.
Mechanism of the Wacker-Tsuji Oxidation
The mechanism is typical of palladium olefin chemistry, and water serves as the oxygen source; the reduced palladium is reoxidized by Cu(II) and ultimately by atmospheric oxygen.
J. Tsuji, "Palladium Reagents and Catalysts", First Edition 2004, Wiley, 29-35.
Wacker-Type Oxidation and Dehydrogenation of Terminal Olefins Using Molecular Oxygen as the Sole Oxidant without Adding Ligand
Y.-F. Wang, Y.-R. Gao, S. Mao, Y.-L. Zhang, D.-D. Guo, Z.-L. Yan, S.-H. Guo, Y.-Q. Wang, Org. Lett., 2014, 16, 1610-1613.
Convenient and Efficient Pd-Catalyzed Regioselective Oxyfunctionalization of Terminal Olefins by Using Molecular Oxygen as Sole Reoxidant
T. Mitsudome, T. Umetani, N. Nosaka, K. Mori, T. Mizugaki, K. Ebitani, K. Kaneda, Angew. Chem. Int. Ed., 2006, 45, 481-485.
The use of tert-butyl nitrite as a simple organic redox cocatalyst instead of copper or silver salts enabled an aldehyde-selective aerobic Wacker-Tsuji oxidation. Various aldehydes could beg isolated as major products in up to 30/1 regioselectivity as well as good to high yields at room temperature.
X.-S. Ning, M.-M. Wang, C.-Z. Yao, X.-M. Chen, Y.-B. Kang, Org. Lett., 2016, 18, 2700-2703.
A General and Efficient Catalyst System for a Wacker-Type Oxidation Using TBHP as the Terminal Oxidant: Application to Classically Challenging Substrates
B. W. Michel, A. M. Camelio, C. N. Cornell, M. S. Sigman, J. Am. Chem. Soc., 2009, 131, 6076-6077.
Wacker-Type Oxidation of Internal Alkenes using Pd(Quinox) and TBHP
R. J. DeLuca, J. L. Edwards, L. D. Steffens, B. W. Michel, X. Qiao, C. Zhu, S. P. Cook, M. S. Sigman, J. Org. Chem., 2013, 78, 1682-1683.