Carboxyl derivatives allylic sources

In scientific and patent literature on diene polymerization the following Nd(III)-salts are most often cited as catalyst precursors halides, carboxylates, alcoholates, phosphates, phosphonates, allyl compounds, cyclopentadienyl derivatives, amides, boranes and acetylacetonates. The catalyst systems based on these Nd-sources are reviewed in the following subsections. 

Allylic sources attack carboxyl derivatives such as esters almost exclusively on carbon by the path AdN, then Ep. As in Section 8.5.5, the enolate source should be the deprotonated sink or the sink should not be enolizable. A final proton transfer to give a resonance delocalized stable anion is frequently the driving force for the reaction. 

Esters of allylic alcohols with resin-bound carboxylic acids can be converted into allyl palladium complexes, which react with carbon nucleophiles and with hydride sources to yield the formally reduced allyl derivatives (Entries 3 and 4, Table 3.47). Alkyl sulfonates have been reduced to alkanes with NaBH4 (Entry 5, Table 3.47). Aryl sulfonates (Entry 6, Table 3.47) and aryl perfluoroalkylsulfonates [814] can be reduced to alkanes by treatment with catalytic amounts of Pd(II) and formic acid as a hydride source. 

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