- Tetrafluorine-containing ketones and acetoacetates: Synthesis and mechanistic study
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Addition of trimethylsilyl trifluoroacetate to the carbanions of α-fluorobenzyl-phosphonate (3) or diisopropyl(fluorocarbethoxymethyl) phosphonate (9) formed the corresponding intermediates [CF3C(O)CFPh] -Li+ (10) and [CF3C(O)CFCO2Et] -Li+ (11), respectively. Subsequent protonation, alkylation or allylation of 10 and 11 afforded trifluoromethyl fluorobenzyl ketones 12 and ethyl 2,4,4,4-tetra-fluoroacetoacetates 13. Based on the results obtained, a plausible mechanism was proposed.
- Tsai, Hou-Jen,Hsieh, Chi-Wei
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p. 749 - 757
(2008/03/11)
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- Synthesis of phenyl and ester substituted vinyl fluorides via reduction and olefination of esters
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A reduction-olefination sequence has been used to convert ethyl pentafluoropropanoate 6 to 1-fluoro-1-phenyl-2-pentafluoroethyl ethene 7 and ethyl 2,4,4,5,5,5-hexafluoro-2-pentenoate 8. Addition of lithium diethyl α-fluorobenzylphosphonate [(EtO)2P(O)CFPh]- Li+ 4 or lithium fluorocarboethoxymethylene dialkylphosphonate [(RO)2P(O)CFCO2Et]- Li+ 5 (R = Et, i-Pr) to a THF solution of fluorinated aldehydes prepared in situ from 6 and diisobutylaluminum hydride (DIBAL) affords the vinyl fluorides C2F5CH=CFPh 7 and C2F5CH=CFCO2Et 8 in good yields. However, yields of the final products 7 and 8 are low when in situ reduction of 6 to aldehyde was performed in the presence of lithium salts of 4 or 5.
- Tsai, Hou-Jen,Burton, Donald J.
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p. 135 - 145
(2007/10/03)
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- Application of fluorocarbethoxy-substituted phosphonate: A facile entry to substituted 2-fluoro-3-oxoesters
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Diethyl(fluorocarbethoxymethyl)phosphonate 1a or diisopropyl(fluorocarbethoxymethyl)phosphonate 1b, prepared from triethyl phosphite or triisopropyl phosphite with ethyl bromofluoroacetate, react with n-butyllithium in THF to give the corresponding phosphonate carbanions [(RO)2P(O)CFCO2Et]-Li+ 2a (R = Et) and 2b (R = i-Pr). Addition of trimethylsilyltrifluoroacetate CF3C(O)OSiMe3 to a THF solution of phosphonate carbanions formed the enolate of ethyl trifluoroacetylfluoroacetate [CF3C(O)CFCO2Et]-Li+ 3. Subsequent protonation, alkylation or allylation of the enolate afforded substituted 2,4,4,4-tetrafluoro-3-oxoesters CF3C(O)CFR1CO2Et 10.
- Tsai, Hou-Jen
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- A Convenient Synthesis of Ethyl (Diethoxyphosphoryl)fluoroacetate from Ethyl Fluoroacetate
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A new synthesis of ethyl (diethoxyphosphoryl)fluoroacetate starting from ethyl fluoroacetate is described for a mole scale.This synthesis does not require the use of special equipment for fluorine chemistry since no hydrogen fluoride is evolved.
- Elkik, Elias,Imbeaux, Michele
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p. 861 - 862
(2007/10/02)
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