The nitro group of dimethyl (1-nitromethylalkyl)phosphonates is conveniently converted into a formyl group by reaction with singlet oxygen to give dimethyl (1-formylalkyl)phosphonates. (1-Formylbutyl)diphenylphosphine oxide is prepared by the same reaction.
A convenient and mild procedure is developed for -nitrophosphonates via phospha-Michael addition of phosphites to nitrostyrene at room temperature in the presence of 1,8-diazabicyclo-[5.4.0]undec-7-ene (DBU)-based ionic liquid [DBUH][OAc]. The operational simplicity, convenient workup, and reusability of the ionic liquid make this method attractive.
Pudowik; Sitdikowa, Doklady Akademii Nauk SSSR, 1959, vol. 125, p. 826