Hypervalent-iodine mediated one-pot synthesis of isoxazolines and isoxazoles bearing a difluoromethyl phosphonate moiety

A one-pot, regioselective 1,3-dipolar cycloaddition of in situ generated (diethoxyphosphoryl)difluoromethyl nitrile oxide toward selected alkenes and alkynes is reported. This protocol enables facile access to 3,5-disubstituted isoxazolines and isoxazoles bearing a CF 2 P(O)(OEt) 2 moiety in good to excellent yields, under mild reaction conditions. A one-step, regioselective procedure to an unexplored class of isoxazolines and isoxazoles bearing a difluoromethyl phosphonate group is reported.