Dienophile in Diels-Alder and related reactions. For addition to a bis-allene, followed by dimerization to a paracyclophane, see: Org. Synth. Coll., 7, 485 (1990). For use in the masking of double bonds for subsequent release by cycloreversion, see: J. Org. Chem., 44, 962 (1979). Review of cycloreversion reactions in organic synthesis: Synthesis, 121 (1985). Used in synthesis of a wide variety of heterocyclic systems including benzo[b]thiophenes from thiophenols: Acta Chem. Scand., 27, 595 (1973), and chromones from phenols: Austral. J. Chem., 48, 677 (1995).Stabilized anions derived from cyclic ?-keto phosphonates undergo ring expansion, via a tandem Michael-Aldol-fragmentation mechanism, to give phosphonates with an additional two carbons in the ring, thus providing a route to highly functionalized medium ring compounds: J. Org. Chem., 60, 3084 (1995). Reacts with activated carbonyl compounds, such as ɑ-keto esters or ɑ-keto nitriles, in the presence of triphenylphosphine, to give highly functionalized -butyrolactones: J. Org. Chem., 61, 4516 (1996).
