3, 3-Diallyldihydrofuran-2, 4-diones with two identical allyl residues were obtained by Tsuji– Trost-type Pd-catalysed allylation of either 4-O-allyltetronates or 3-allyltetronic acids. Allylation of sodium 3-allyltetronate with a second allyl acetate gave mixed derivatives as did the Claisen rearrangement of 4-O-allyl 3-allyltetronates under microwave conditions. Compounds and were converted to butanolides with 3, 3-spirocyclopentenyl or 3, 4- ...