Production of compounds having at least one -CF2-O- bridge, useful for liquid crystal displays, comprises reaction of a bis(alkylthio)carbenium salt with a hydroxyl group containing compound.

摘要

A process for the production of compounds (I) having at least one -CF2-O- bridge in the molecule comprises reaction of a bis(alkylthio)carbenium salt with a hydroxyl group containing compound in the presence of a base and followed, preferably in-situ, by oxidative fluorination using a fluorinating agent and an oxidizing agent to form the compound (I). Independent claims are included for : (i) a bis-(alkylthio)carbenium salt of formula (I) (ii) a dithioorthoester of formula (II) R1 = 1-12C alkyl or alkoxy, optionally monosubstituted by -CN, -CF3 or halogen, 2-12C oxyalkyl, alkenyl or alkenyloxy, 3-12C oxyalkenyl optionally containing -O-, -S-, -CO-, -CO-O-, -O-CO- or -O-CO-O- groups in place of one or more non-neighboring CH2 groups; A = cis or trans- 1,4-cyclohexylene, 1,4-phenylene or 1,4-cyclohex-3-enylene optionally mono- or di-substituted by halogen, preferably fluorine, pseudohalogen, -OCF3 or -OCHF2; Z = a single bond, -CH2CH2-, -CF2-CF2-, -CF2-CH2, -CH2CF2-, -CF=CF-, -CH=CH-, -CC-, -CO-O-, -O-CO-, -CF2-O- or -O-CF2-; -S-(CR2R3)n-S- is a bridging group; R2, R3 = alkyl, alkenyl or together form a cycloalkyl or aryl group; m = 0-6; n = 2 or 3; Y- = an anion; o = 0-6; for formula (2) R1 = additionally -H, -F, -Cl, -CN, -NCS, -OCF3 or -OCHF2