Reaction of thioglycolate with α-fluoro-β-(phenylthio)enones (or -enals): Synthesis of substituted α-carboxy-γ-fluorothiophenes
摘要:
A new synthetic method to substituted alpha-carboxy-gamma-fluorothiophenes 2F is reported. They were prepared by the reaction between two equivalents of methyl thioglycolate anion and alpha-fluoro-beta-(phenylthio)enones (or -enals) 1F, in DMSO (70 degrees C) in yields ranging from 41% to 85%. We show from the reaction of (Z)-alpha-fluoro-beta-(phenylthio)but-enone 1aF, that cyclisation to fluorothiophene 2aF occurs via the formation of stable enolates of alpha-fluoro-beta-(dithianyl)butanone. (C) 1997, Elsevier Science Ltd.
THE SILA-PUMMERER REARRANGEMENT OF 1-ALKYL-3-PHENYLSULFINYL-3-TRIMETHYLSILYLCYCLOBUTANOLS. A NEW METHOD FOR THE PREPARATION OF 3-ALKYL-2-CYCLOBUTENONES
3-Alkyl-2-cyclobutenones were produced by the sila-Pummerer rearrangement of 1-acetoxy-1-alkyl-3-phenylsulfinyl-3-trimethylsilylcyclobutanes followed by hydrolysis. β-Phenylthio-α,β-and β,γ-unsaturated ketones were major products when the corresponding cyclobutanols were employed.
The synthesis of two isomeric isoxazoles could be selectively controlled in the reaction of β-substituted enones with 3 species of hydroxylamine; hydroxyammonium cation (1), free hydroxylamine (2) and aminohydroxy anion (3).