Di-tert-butyl P, P-difluorooxaloacetate, prepared by fluorination of di-tert-butyl oxaloacetate with perchloryl fluoride, was converted to di-tert-butyl@,@-difluoroaspartate via its 0-methyl oxime, followed by reduction. The tert-butyl ester was hydrolyzed to give a mixture of dl-P, P- difluoroaspartic acid, which was resolved via its brucine salts. dl-Difluoroaspartic acid was converted into P, P-difluoroasparagine by monoesterification and subsequent ...
[Bijeire, Laurent; Denier, Colette; Mulliez, Michel; De Lima, Waldir Tavares Phosphorus, Sulfur and Silicon and the Related Elements, 2007 , vol. 182, # 4 p. 881 - 891]