Novel alkylation, lactonisation and cascade coupling processes mediated by lead tetracarboxylates: the importance of ligands

The reactions of lead(IV) tetracarboxylates with carboxylic acids containing unsaturated side chains is reported. At elevated temperature in toluene, facile decarboxylation or lactonisation processes are observed, depending on the length of the carboxylate side chain and in some cases further cascade coupling processes with added nucleophiles are possible. The efficiency of these processes depends on the structure of the carboxylate ligand and the mechanistic implications of these results are briefly discussed.