Hydrogenation of fluorine-containing cyclohexene derivatives, useful in preparation of liquid crystal materials, in presence of basic ion exchanger that inhibits defluorination

摘要

Method for hydrogenation of specific polycyclic cyclohexene derivatives (I) and (II) to the corresponding cyclohexanes, in which a palladium-based catalyst (A) is used in presence of a basic ion exchanger. Method for hydrogenation of polycyclic cyclohexene derivatives of formulae (I) and (II) to the corresponding cyclohexanes, of formulae (III) and (IV), in which a palladium-based catalyst (A) is used in presence of a basic ion exchanger. n = 0 or 1; OY1 and OY2 = base-stable protecting groups for a keto group, optionally linked together to form a ring; L1-L4 = hydrogen or fluoro; and R = hydrogen, fluoro, chloro, trifluoromethyl, trifluoromethoxy or difluoromethoxy; with the proviso that at least one of R and L1-L4 must be fluoro.