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A simple method for the preparation of phosphorus-containing pyrimidine analogues such as 2,5-dihydro-2-ethoxy-1,5,2-diazaphosphinine 2-oxides 9 , 12–15 and adducts 3 , 10 is described. Dihydrophosphinines 9 , 12–15 are prepared from primary enamine phosphonates and nitriles or from phosphonates and nitriles in the presence of base, while highly stable hydrogen-bonded amine-dihydro-diazaphosphinine adducts 3 , 10 are obtained by the addition of amine to dihydrophosphinines 9 or by reaction of alkylphosphonates with nitriles in the presence of LDA.

A simple and efficient method for asymmetric synthesis of 2 H -azirine-2-phosphonates 6 is described. The key step is a base-mediated Neber reaction of p -toluenesulfonyloximes 4 derived from phosphonates. Triethylamine 5 , alkaloids 7 and solid-phase bound achiral 8 or chiral amines 9 are used. Reduction of 2 H -azirines 6 with sodium borohydride in ethanol gives cis -aziridine-phosphonates 10 . Ring opening of aziridines 10 and 11 leads to the formation of enantiomerically enriched β- 12 and 14 and α-aminophosphonates 13 and 15 .