5-(3-Phosphonated 1H-1,2,3-triazol-4-yl)isoxazolidines: synthesis, DFT studies and biological properties

5-Triazolyl-2-methylisoxazolidin-3-yl 3-phosphonates have been synthesized by 1,3-dipolar cycloaddition of N-methyl-C-diethoxyphosphorylnitrone and vinyl triazoles. The process showed a complete regioselectivity and a nearly exclusive cis stereoselectivity. M062X/6-31G(d,p) calculations rationalize the regio- and the stereochemical results. The formation of a hydrogen bond along a particular reaction channel significantly stabilizes both transition states and products related to cis-adducts. Biological tests indicate that the obtained compounds do not show relevant antiviral and anticancer activity