Process for the preparation of a compound of the general formula R-(A 1 -Z-)m B-CF 2 O-A 2 -(A 3) n -R' in which R denotes alkyl, in which one or more CH 2 groups may be replaced, independently of one another, by O, CF 2, CH=CH, CH=CF, CF=CF, with the proviso that peroxide structures O-O and formaldehyde acetals O-CH 2 -O are excluded, A 1, independently of one another, denotes 1,4-cyclohexylene, 2,5-1,3-dioxanylene, 1,3-cyclobutylene or A 2, A 3 denote 1,4-phenylene, in which, independently of one another, one to four hydrogens may be replaced by fluorine or one or two CH groups may be replaced by N, Z denotes a single bond, -CH 2 -CH 2 -, -CF 2 -CF 2 -, -CH=CH-, -CF=CF-, -CH=CF- or -CF=CH-, B denotes 2,6-disubstituted trans-decalin, R' denotes R, F, OCF 3, OCF 2 H, CF 3, Cl, SF 5, CN, NCS, and m, n, independently of one another, denote 0 or 1, comprising the following steps: a) conversion of a compound of the general formula R-(A 1 -Z-) m BX, in which X denotes a halogen and the other symbols have the meaning indicated in relation to formula, into the corresponding Grignard compound, reaction of the resultant Grignard compound with CO 2 and hydrolysis to give the corresponding carboxylic acid of the formula R-(A 1 -Z-) m B-CO 2 H, b) conversion of the carboxylic acid of the formula into the corresponding bisalkylthionium salt and reaction of this salt with a phenol of the general formula HO-A 2 (-A 3) n -R', in which A 2, A 3, R' and n have the meaning indicated in relation to formula, under water-eliminating conditions to give the corresponding ester, and c) conversion of the ester obtained into the corresponding ether of the general formula in an oxidative fluorodesulfuration. R denotes alkyl, in which one or more CH 2 groups may be replaced, independently of one another, by O, CF 2, CH=CH, CH=CF, CF=CF, with the proviso that peroxide structures O-O and formaldehyde acetals O-CH 2 -O are excluded, A 1, independently of one another, denotes 1,4-cyclohexylene, 2,5-1,3-dioxanylene, 1,3-cyclobutylene or A 2, A 3 denote 1,4-phenylene, in which, independently of one another, one to four hydrogens may be replaced by fluorine or one or two CH groups may be replaced by N, Z denotes a single bond, -CH 2 -CH 2 -, -CF 2 -CF 2 -, -CH=CH-, -CF=CF-, -CH=CF- or -CF=CH-, B denotes 2,6-disubstituted trans-decalin, R' denotes R, F, OCF 3, OCF 2 H, CF 3, Cl, SF 5, CN, NCS, and m, n, independently of one another, denote 0 or 1, a) conversion of a compound of the general formula R-(A 1 -Z-) m BX, in which X denotes a halogen and the other symbols have the meaning indicated in relation to formula, into the corresponding Grignard compound, reaction of the resultant Grignard compound with CO 2 and hydrolysis to give the corresponding carboxylic acid of the formula R-(A 1 -Z-) m B-CO 2 H, b) conversion of the carboxylic acid of the formula into the corresponding bisalkylthionium salt and reaction of this salt with a phenol of the general formula HO-A 2 (-A 3) n -R', in which A 2, A 3, R' and n have the meaning indicated in relation to formula, under water-eliminating conditions to give the corresponding ester, and c) conversion of the ester obtained into the corresponding ether of the general formula in an oxidative fluorodesulfuration.