Diethyl Fluoronitromethylphosphonate: Synthesis and Application in Nucleophilic Fluoroalkyl Additions

Diethyl fluoronitromethylphosphonate ( 3 ), a previously unknown compound, was synthesized by electrophilic fluorination of diethyl nitromethylphosphonate with Selectfluor. Base‐induced decomposition of 3 was studied by NMR spectroscopy, which identified diethyl fluorophosphate and fluoronitromethane as the main decomposition products. C?H acidities pK_a values in dimethyl sulfoxide (DMSO)] of 3 , 1‐fluoro‐1‐phenylsulfonylmethanephosphonate ( 1 ; McCarthy’s reagent), tetraethyl fluoromethylenebisphosphonate ( 2 ), and some nonfluorinated phosphonates were computed, and a good correlation between calculated and experimental pK_a values was found. The calculated C?H acidities increased in the sequence 2 < 1 < 3 . Diethyl fluoronitromethylphosphonate ( 3 ) was applied in the Horner–Wadsworth–Emmons reaction with aldehydes and trifluoromethyl ketones to provide new 1‐fluoro‐1‐nitroalkenes with good to high stereoselectivities. Alkylation of 3 was successful only with iodomethane, however, conjugate additions of 3 to Michael acceptors such as α,β‐unsaturated carbonyl compounds, sulfones, and nitro compounds allowed access to variously modified diethyl 1‐fluoro‐1‐nitrophosphonates.