ChemInform Abstract: POLYFLUORIERTE ENOLE UND DEREN DERIVATE 1. MITT. DARST. METASTABILER ENOLFORMEN EINIGER POLYFLUORACETONE

Abstract

Durch Reaktionen der Polyfluoracetone (I) mit Triisopropylphosphit bei 0‐80°C werden die Enolphosphate (II) dargestellt.

A New Strategy for the Synthesis of α-Difluoromethyl-Substituted α-Hydroxy and α-Amino Acids

“…The enol of pentafluoroacetone (as an analog of 4 ) quantitatively isomerizes to give the ketone in boiling MeOH . All attempts to induce complete transformation of 4 into ketone 5 were unsuccessful so far.…”

Synthesis and reactivity of fluorine-containing thiols and thioacyl halides

“…11 We failed to detect pentafluorothioacetone in [4+2] cycloaddition reactions with cyclopentadiene in solutions (also in base catalyzed reactions).…”

Fluorine-containing alkyl(aryl) vinyl sulfides

“…37 Unlike internal alkenes, fluoroalkenes with a terminal double bond are usually converted into addition products at the C=C bond when they react with thiols in the presence of organic bases; in some cases, the reaction mixtures contain vinylic substitution products as impurities (up to 20%). 3,4,40,41 An exception to this rule is the dimethylamide of perfluoromethacrylic acid (9), which reacts with PhSH and PhCH 2 SH to give products of replacement of the fluorine atom 10 (as a mixture of cis-and trans-isomers according to 19 F NMR data) apart from hexafluoroisobutyric dimethylamide. 42 This outcome was explained in the study cited by the noticeable basicity of the dimethylamide group, which can trap the eliminated proton thus preventing its addition to the carbanion centre.…”

“…occurs when this compound is heated to 120 8C in trifluoroacetic acid in a sealed tube. 116 The intramolecular cyclisation of 5-methoxy-2-trifluoromethylthiopenta-2,4-dienonitrile (41) induced by HBr and AcOH involves the nitrile group. This reaction was patented as a method of synthesis of 3-trifluoromethylthio-substituted pyridines.…”