科研之友
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摘要
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 alpha,beta-unsaturated carbonyl compounds, sulfones, and nitro compounds allowed access to variously modified diethyl 1-fluoro-1-nitrophosphonates.
- 出版日期2014-1-27
