Substituted allylmalonates undergo the selective C-C bond cleavage in the presence of triethylaluminum and a catalytic amount of nickel and ruthenium phosphine complexes, resulting in the loss of the allyl moiety and formation of monosubstituted malonates. Comparison of reactivity of the nickel and ruthenium complexes showed that the use of the former is general with respect to the structure of the substituted allylmalonates, and the activity of the latter depended on the substitution pattern of the double bond of the allylic moiety. The smooth deallylation may encourage the use of the allyl group as a protective group for the acidic hydrogen in malonates.

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Various allylmalonates and other related compounds were selectively deallylated in the presence of a catalytic amount of a rhodium complex and an excess of triethylaluminum. Comparison of several phosphane (PPh 3 ) and BIAP (bis(imidazolonyl)pyridine) rhodium complexes showed that the latter are more active and general with respect to the structural diversity of the substrate then the former. It was shown that the role of triethylaluminum is not only to generate in situ a rhodium hydride, which is assumed to be the catalytically active species, but also to act as a Lewis acid to activate the carbonyl group of the substrate. Thus, the proposed mechanism of deallylation involves hydrorhodation of the double bond along with activation of the carbonyl group of the substrate by triethylaluminum followed by a sequence of bond formations and cleavages, furnishing an enolate and an alkene. The methodology provides an efficient and selective route to deallylation of allylmalonates under mild reaction conditions.