Acyl fluondes hydrogen fluonde

During electrochemical fluorination retention of important functional groups or atoms in molecules is essential. Acyl fluorides and chlorides, but not carboxylic acids and anhydrides (which decarboxylate), survive perfluorination to the perfluorinated acid fluorides, albeit with some cyclization in longer chain (>C4) species [73]. Electrochemical fluorination of acetyl fluoride produces perfluoro-acetyl fluoride in 36-45% yields [85]. Electrochemical fluorination of octanoyl chloride results in perfluorinated cyclic ethers as well as perfluorinated octanoyl fluonde. Cyclization decreases as initial substrate concentration increases and has been linked to hydrogen-bonded onium polycations [73]. Cyclization is a common phenomenon involving longer (>C4) and branched chains. a-Alkyl-substituted carboxylic acid chlorides, fluorides, and methyl esters produce both the perfluorinated cyclic five- and six-membered ring ethers as well as the perfluorinated acid... 

Removal of the TBDPS ether in intermediate 71-1 en route to Myxovirescin A1 [Scheme 4.71] gave the desired alcohol 71.2 along with the acyl migration product 71 3.126 With TBAF, a 1 1 mixture of 71,2 and 71,3 was obtained but the rearrangement was minimised to 10% using the hydrogen fluonde-triethylamine complex at room temperature. 

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