Ligand synthesis carbon nucleophile-palladium 77-complexes

When the Pd bears chiral ligands, these reactions can be enantioselective.1448 ir-Allylmo-lybdenum compounds behave similarly.1449 Because palladium compounds are expensive, a catalytic synthesis, which uses much smaller amounts of the complex, was developed. That is, a substrate such as an allylic acetate, alcohol, amine, or nitro compound1450 is treated with the nucleophile, and a catalytic amount of a palladium salt is added. The rr-allylpal-ladium complex is generated in situ. Alkene-palladium complexes (introducing the nucleophile at a vinylic rather than an allylic carbon) can also be used.1451... 

In contrast to the processes based on the external attack of a nucleophile on the coordinated CO or olefin ligands on Pd(II) species, where re-oxidation of the Pd(0) produced to reactive Pd(II) presents a considerable problem, no such problem is involved in reaction of a Pd(0) complex with allylic substrates. As we have already discussed in Schemes 1.9 and 1.10, allylic compounds such as allylic acetates or carbonates readily oxidatively add to Pd(0) species to form 7 -allyl palladium(II) complexes that are susceptible to nucleophilic attack. The catalytic process converting allylic substrates to produce allylation products of nucleophiles has found extensive uses in organic synthesis, notably in the work of Tsuji and Trost. Employment of a chiral ligand in the catalytic allylation of nucleophiles allows catalytic asymmetric synthesis of allylation... 

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