[Reaction: see text]. Seven-membered cyclic alpha-monofluorophosphonate esters such as 2-allyloxy-3-fluoro-3-phenylthio-4,7-dihydro-[1, 2]-oxaphosphinine-2-oxide were successfully synthesized in moderate total yield as 41% from open-chain allyl phosphonates having an alpha-arylthio group as an electroauxiliary using an alternative sequence of anodic fluorination and ring-closing olefin metathesis (RCM). On the other hand, in an attempt to synthesize an eight-membered analogue, a different type of seven-membered fluorinated cyclic product was formed predominantly by the RCM reaction between the allyloxy groups.

No abstract

Regioselective anodic a-fluorination of a-(arylthio)benzylphosphonate esters and [(arylthio)methyl]-and [(heteroarylthio)methyl]phosphonate esters was successfully carried out at a glassy carbon anode or platinum anode in dimethoxyethane and nitromethane to provide the corresponding a-fluorophosphonate esters in excellent to moderate yields.

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Organo-phosphorus compounds S 0080Electrolytic Partial Fluorination of Organic Compounds. Part 84. Anodic Monoand Difluoronation of Benzylphosphonate Derivatives. -Fluorination of benzylphosphonate derivatives (I) under various electrolytic conditions affords the α-mono-(II) and/or α,α-difluoro-products (III) in moderate to good yields. The anodic fluorination depends on the electrolytic solvents and supporting fluoride salts as well as on the structures of the substrates and the electrolytic conditions. For instance, the increase of electricity in the anodic fluorination of p-methoxybenzylphosphonate (Ib) results in the formation of α,α-difluoro-p-methoxybenzylphosphonate (IIIb) exclusively. Fluoroproducts (IIe) and (IIIe) are useful intermediates since they are easily converted into phosphonylated tyrosine moieties. -(ZAGIPA, B.; HIDAKA, A.; CAO, Y.; FUCHIGAMI*, T.; J. Fluorine Chem. 127 (2006) 4-5, 552-557; Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 226, Japan; Eng.) -H. Hoennerscheid 38-161