Nitroxide chemistry. Part 18. Reaction of bistrifluoromethyl nitroxide with some ethers

Abstract

Treatment of the methyl ethers MeOX (X = Me, Ph) with a stoicheiometric amount of bistrifluoromethyl nitroxide [(CF₃)₂NO·= R·] at room temperature converts them efficiently into their bistrifluoromethylamino-oxymethyl counterparts, RCH₂OX; the bis-derivative (RCH₂)₂O is a minor by-product in the case of dimethyl ether (X = Me). Multiple hydrogen-abstraction increases in importance with diethyl ether as substrate, the expected products RCHMeOEt and (RCHMe)₂O being accompanied by a bis-derivative (RCH₂CHROEt) arguably produced via the αβ-dehydrogenation 2R·+ Et₂O → 2RH + CH₂CHOEt. The halogeno-ether MeOCF₂CHFCl reacts slowly with the nitroxide at 50 °C to yield a 7 : 1 mixture of the derivatives RCH₂OCF₂CHFCl and RCFClCF₂OMe, hydrolysis of which gives the esters RCH₂OCOCHFCl and RCFClCO₂Me, respectively. The latter ester is best obtained via treatment of methyl chlorofluoroacetate with bistrifluoroacetate with bistrifluoromethyl nitroxide.