Fluoro-ketones. V reaction of alkyl and aryllithium compunds with perfluoroalkylether esters

n-Butyllithium and a variety of aryllithium compounds have been shown to react with a perfluoroalkylether ester (R_fOR_fCO₂R) at ?78°C to produce perfluoroalkylether ketones. In the absence of competing reactions, which may be due to additional reactive groups on the ester, high yields of ketones can be prepared. Steric hindrance adjacent to the carbonyl group has an important effect on rates of reactions. Low reaction temperature ?78°C is an important factor when secondary esters are used. At higher reaction temperatures >;?30°C, the secondary esters produce decreased yields of ketone due to the instability of the intermediate lithium salt of the hemiketal which decomposes to an aryl ester and a perfluorinated olefin.