For use of ?-ketophosphonates in an annulation sequence for building a cyclohexadienone ring onto a cyclic ketone, see: Synthesis, 855 (1982). Successive treatment with NaH and n-BuLi gives the dianion which can be alkylated or acylated on the terminal position: see. e.g.: Synth. Commun., 22, 219 (1992); J. Chem. Soc., Perkin 1, 2259 (1998).