Active methylene compounds coupling with allylic

With the introduction of the highly reactive allylic carbonates, coupling reactions can be carried out under neutral conditions. This is especially important when dealing with compounds that are sensitive to bases. The oxidative addition of allylic carbonates is followed by decarboxylation as the irreversible step to produce the 71-allylpal-ladium alkoxides. Since the alkoxides produced are rather poor nucleophiles, they do not compete with the carbon nucleophile for the 7i-allylpalladium complex but do deprotonate the active methylene compound. Attack of the Nu on the 7i-allylpalladi-um complex leads to the substitution product. 

Substitution of allylic alcohols with active methylene compounds as a suspension in water was achieved in excellent yields using Pd(PPhj)4 in the presence of a carboxylic add such as l-adamantanecarboxyUc add. Bergbreiter and Liu used a water-soluble, polymer-bound paUadium/phosphine catalyst in water or in mixed aqueous/organic solvents. This polymeric catalyst showed high activity in nucleophilic allylic substitution affording high yields of coupled products, and it could be recycled by solvent or thermal precipitation. 

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