Tetrahydropyran compounds

A tetrahydropyran compound of formula I

• in which
• R1 and X1 denote H, an unsubstituted or mono- or poly-halogen-sub-stituted alkyl or alkoxy radical having 1 to 15 carbon atoms or alkenyl or alkenyloxy radical having 2 to 15 carbon atoms, in which one or more CH2 groups are optionally each, independently of one another, replaced by —C≡C—, —CH═CH—, —CF═CF—, —O —, —(CO)O—or —O(CO)— in such a way that O atoms are not linked directly to one another;
• or one of the radicals R1 and X1 also denotes F, Cl, CN, NCS or SF5,
• rings A1 and A2 denote, independently of one another, 1,4-cyclohexylene, 1,4-cyclohexenylene or 1,4-cyclohexadienylene, which are unsubstituted or substituted by 1 to 3 F,
• L1 and L2 denote, independently of one another, H or F,
• m denotes 0 or 1 and
• n denotes 1, 2 or 3,
• where m+n is≧2.