Fluorocyclohexene derivatives, and liquid-crystalline medium

A difluorocyclohexane compound of formula III

• R3—A*—(Z6—A7)m—Z7—Qr—R4 III
• wherein
• R3 and R4, independently of one another, are each H, alkyl having 1-12 carbon atoms, or alkyl having 1-12 carbon atoms in which one or more CH2 groups are each, independently of one another, replaced by —O—or —CH═CH— in such a way that heteroatoms are not connected directly;
• A7 is in each case, independently of one another, trans-1,4-cyclohexylene radical, wherein one or more non-adjacent CH2 groups may in each case, independently, be replaced by —O—or —S—, and where the radical may be monosubstituted by Cl or F,
• Z6 and Z7 are each, independently of one another, —CO—O—, —O—CO—, —CH2O—, —O—, —O—CH2—, —CH2CH2—, —CH═CH—, —C≡C—, —CF2CF2—, —OCF2, —CF2O—, —CH2CF2—, —CF2CH2— or a single bond;
• m is 0, 1, 2 or 3;
• r is 0 or 1;
• and
• m+r is 1, 2 or 3;
• with the proviso that compounds in which
• m is 1,
• r is 0,
• Z6 is a single bond,
• A7 is cyclohexane-1,4-diyl and
• R3 and R4 are alkyl, or alkyl in which, one CH2 group is replaced by —O—,
• are excluded.

A fluorocyclohexene compound of formula I

• R1—(A1—Z1)n—A—(Z2—A2)m—Z3—B—(Z4—A3)p—R2 I
• wherein
• R1 and R2, independently of one another, are each H, —CN, —F, —OCHF2, —OCF3, —OCHFCF3, —OCH2CF3 or —OCF2CF3, alkyl having 1-12 carbon atoms which is unsubstituted or at least monosubstituted by halogen or CN, wherein one or more CH2 groups of the alkyl groups may in each case, independently of one another, be replaced by —O—, —S—, —CO—,
• —CO—O—, —O—CO—, —O—CO—O— or —CH═CH— in such a way that heteroatoms are not connected directly;
• A is
• A1, A2 and A3 are in each case independently of one another,
• a) a trans-1,4-cyclohexylene wherein one or more non-adjacent CH2 groups may in each case, independently of one another, be replaced by —O—or —S—,
• b) a 1,4-phenylene wherein one or two CH groups may in each case, independently of one another, be replaced by N, and which is unsubstituted or substituted by CN, Cl or F,
• c) 1,4-bicyclo[2.2.2]octylene, piperidine-1,4-diyl, naphthalene-2,6-diyl, decahydronaphthalene-2,6-diyl, or 1,2,3,4-tetrahydronaphthalene-2,6-diyl,
• d) 1,4-cyclohexenylene,
• B, is trans-1,4-cyclohexylene, in which one or more non-adjacent CH2 groups may in each case, independently of one another, be replaced by —O—or —S—,
• X1 and X2, independently of one another, are each F, Cl, CN, CF3 or CHF2;
• Z1, Z2,
• and Z4 are each, independently of one another, —CO—O—, —O—CO—, —CH2O—, —O—, —O—CH2—, —CH2CH2—, —CH═CH—, —C≡C—, —CF2CF2—, —OCF2—, —CF2O—, —CH═CF—, —CF═CH— or a single bond;
• Z3 is —CO—O—, —O—CO—, —CH2O—, —O—, —O—CH2—, —CH2CH2—, —CH═CH—, —C≡C—, —CF2CF2—, —OCF2—, —CF2O—, —CH═CF—, or —CF═CH—;
• n is 0;
• m is 0, 1, 2, or 3;
• p is 0, 1, 2, or 3;
• and
• m+n+p is 0, 1, 2 or 3.