The invention provides novel insecticidally useful fluorinated ethers of formula :
where Ar and Y are both substituted aryl groups, Z is a lower fluoroalkyl group (eg. trifluoromethyl), X' is hydrogen and X is hydrogen, halo, hydroxy, alkoxy or acyloxy, as well as the compounds where X and X' form a second bond between the adjacent carbon atoms. A typical example is 1,1,1-trifluoro-2-(4-ethoxyphenyl)-3-(4-fluoro-3-phenoxybenzyloxy)propane. The invention also provides novel intermediates for the preparation of the compounds including those of formulae ArCH(CF3)CH2OH, ArC(OH)(CF3)CH2OH, ArC(OH) (CF3)CH2Hal and