Perfluoro esters, eliminative

A tertiary radical can be formed by elimination during AF of ter/-butyl methyl and ethyl ethers thus, isolation of the respective perfluoro-/erf-butyl ethers, e.g. 1, occurs in only 36 and 42% yield.28 Significant quantities of perfluoro(2-methylpropane) (2) are also isolated. The longer alkyl chains (ethyl and larger) appear to be slightly less prone to scission than the methyl group. Apparently, carbonyl fluoride is more readily eliminated than trifluoroacetyl fluoride, a phenomenon observed during AF of esters.29 Elimination becomes most serious in the special class of polyethers called ortho esters, e.g. 3-5.30 Cyclic ortho esters, acetals and ketals are much less affected than acyclics. 

Carbocarbonylation [216] of alkyl halide with a perfluoro substituent leads directly to the analogous carboxylic acids and esters, provided the ) -hydride elimination is slower than CO insertion. The use of PdCl2(dppf) in the esterification of 68 gives... 

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