Compounds for a liquid-crystalline medium, and the use thereof for high-frequency components

A compound of the formula I

• in which
• A3 denotes
• L1 denotes branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, in which, in addition, one or more —CH2— groups may be replaced, independently of one another, by O, substituted or unsubstituted cycloalkyl, cycloalkenyl, substituted or unsubstituted phenyl, substituted or unsubstituted arylethynyl, fluorinated alkyl or alkenyl, or fluorinated alkoxy or alkenyloxy, or L1 denotes F, Cl, Br, CN, NCS or SF5,
• L2 denotes branched or unbranched alkyl, alkenyl or alkynyl having 1 to 12 C atoms, in which, in addition, one or more —CH2— groups may be replaced, independently of one another, by O, substituted or unsubstituted cycloalkyl, cycloalkenyl, substituted or unsubstituted phenyl, substituted or unsubstituted arylethynyl, fluorinated alkyl or alkenyl, fluorinated alkoxy or alkenyloxy,
• L3 and L4 independently are as defined for L1 or denote H,
• R1 and R2, independently of one another, denote a halogenated or unsubstituted alkyl radical having 1 to 15 C atoms, where, in addition, one or more CH2 groups in these radicals may each be replaced, independently of one another, by —C≡C—, —CH═CH—, —CF═CF—, —CF═CH—, —CH═CF—, —(CO)— and —O— in such a way that O atoms are not linked directly to one another,
• or denote F, Cl, Br, CN, CF3, OCF3, NCS or SF5,
• or R2 can also denote H,
• A1, A2, A4 and A5 each, independently of one another, denote
• a) 1,4-phenylene, in which one or more CH groups may be replaced by N,
• b) trans-1,4-cyclohexylene or cyclohexenylene, in which, in addition, one or two non-adjacent CH2 groups may be replaced by —O— and/or —S—, and in which H may be replaced by F,
• c) a radical of the formula
• or
• d) a radical selected from 1,4-bicyclo[2.2.2]octylene, cyclo-butane-1,3-diyl, spiro[3.3]heptane-2,6-diyl, thiophene-2,5-diyl, thiophene-2,4-diyl, furan-2,5-diyl, furan-2,4-diyl,
• and in which, in groups a), b), c) and d),
• one or more H atoms may, in addition, be replaced by Br, Cl, F, CN, —NCS, —SCN, SF5, C1-C10 alkyl, C1-C10 alkoxy or a mono- or polyfluorinated C1-C10 alkyl or alkoxy group,
• k denotes 0 or 1,
• Z1 and Z5, independently of one another, denote a single bond, —C≡C—, —CH═CH—, —CH2O—, —(CO)O—, —CF2O—, —CF2CF2—, —CH2CF2—, —CH2CH2—, —(CH2)4—, —CH═CF— or —CF═CF—, where asymmetrical bridges may be oriented to both sides,
• where, for k=0, Z5 is a single bond, and
• m and n, independently of one another, denote 0, 1 or 2.