Organopalladium Wacker oxidation

The first process to be discussed is a traditional one that probably does not occur via a Jt-complex. Nonetheless, it sets the stage for the organopalladium chemistry to be discussed in this section. The Wacker process (or the Wacker oxidation) is used in industry to convert ethylene to acetaldehyde using soluble palladium catalysts.207 in this reaction, ethylene reacts with cupric chloride (CuCl2) and palladium chloride (PdCl2) to... 

Organopalladium derivatives containing Pd(II) can serve as sources of carbocationic species. Both alkene-Pd Tr-complexes and oxypalladated intermediates in the Wacker oxidation reactions can therefore generate carbocationic intermediates, which may then undergo anionotropic rearrangements (Scheme 6). In fact, it is rather remaikable that, despite the well-known involvanent of alkene-Pd Tr-complexes and oxypalladated intermediates, the Wacker-type oxidation of alkenes is relatively free from various possible rearrangement reactions. 

By use of aryl compounds prepared in this way, the arylation of alkenes and a variety of other organic unsaturated compounds can be achieved.52 A palladium compound, usually Li2PdCl4, is used as a transfer agent and organopalladium species are believed to be unstable intermediates by use of air and a Cu" salt the reaction can be made catalytic, since the Pd metal formed in the reaction is dissolved by Cu11 and the Cu1 so produced is oxidized by air (cf. the Wacker process, Section 24-B-5). A typical reaction is... 

In this paragraph, a couple of oxidative processes involving organopalladium species are compiled. The most important (both academic and industrial) reaction was the Wacker reaction, discovered by German chemists from the Wacker company. 

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