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Dialkyl alkynylphosphonites (I) react with esters and nitriles of α-oxocarboxylic acids to give phosphorylated alkanoates, 1,3,2-dioxaphospholanes and 1-phosphabicyclohept-4-enes, depending on the nature of the reagent and conditions of the reaction. The reaction of dialkyl alkenylphosphonites (II) with esters and nitriles of α-oxo-carboxylic acids predominantly leads to dioxaphospholane derivatives.

Dialkyl alkynylphosphonites (I) react with nitrile of trimethylpyruvic acid, and esters of trifluoropyruvic and mesoxalic acids in boiling benzene to form new bicyclic phosphoranes. The reaction proceeds according to the scheme including the formation of bipolar ions (A) and (B), and ylide (C). Addition of the second molecule of carbonyl compound leads to (I).

Hexafluoroacetone (IIa) or methyl trifluoropyruvate (IIb) react with the alkinylphosphonites (I) to give the dioxaphosphabicycloheptene (III).

The title compounds (I) and (II) are combined to give the phosphonates (III).