Ck. Mcclure et al., PENTACOVALENT PHOSPHORUS IN ORGANIC-SYNTHESIS - A NEW ROUTE TO SUBSTITUTED PHOSPHONATES, Phosphorus, sulfur and silicon and the related elements, 75(1-4), 1993, pp. 23-26
The pentacovalent oxaphospholene derived from methyl vinyl ketone and
trialkyl phosphite has been shown to condense with a variety of electr
ophiles to produce highly substituted phosphonates.