EP1937661A1

EP1937661A1 - Spiro [3.3] heptyl-dioxan derivatives and their use in liquid crystal media

Info

Publication number: EP1937661A1
Application number: EP06806163A
Authority: EP
Inventors: Lars Lietzau; Werner Binder; Melanie Klasen-Memmer; Eike Poetsch; Markus Czanta
Original assignee: Merck Patent GmbH
Current assignee: Merck Patent GmbH
Priority date: 2005-10-19
Filing date: 2006-10-11
Publication date: 2008-07-02
Also published as: KR20080072657A; CN101291921A; WO2007045382A1; US7691456B2; US20080251761A1; JP2009515825A

Abstract

The invention relates to novel dioxan derivatives of the formula R1-(A1-Z1)m - G- (Z2-A2)n-R2, in which G represents (I) or (II) and R1, R2, A1, A2, Z1, Z2, m and n are defined as cited in claim 1, to their use as a component or components in liquid crystal media and to liquid crystal and electrooptic display elements, which contain the novel liquid crystal media.

Description

SPIRO [3.3] HEPTYL DIOXAVE DERIVATIVES AND THEIR USE IN LIQUID CRYSTALLINE MEDIA

The present invention relates to dioxane derivatives containing both a dioxane ring and a spiro [3.3] heptyl group as part of their

Framework, their use as component (s) in liquid-crystalline media and liquid crystal and electro-optical display elements containing these liquid-crystalline media according to the invention.

The dioxane derivatives according to the invention can be used as component (s) of liquid-crystalline media, in particular for displays based on the principle of the twisted cell, the guest-host effect, the effect of the deformation of upright phases DAP or ECB (Electrically Controlled Birefringence), the IPS Effect (In Plane Switching) or the effect of dynamic scattering.

The substances used hitherto for this purpose always have certain disadvantages, for example too little stability against the action of heat, light or electric fields, unfavorable elastic and / or dielectric properties.

The invention was thus based on the object of finding new stable compounds which are suitable as component (s) of liquid-crystalline media, in particular for TN, STN, IPS and TFT displays.

Another object of the present invention was to provide compounds which have a low rotational viscosity, have a positive dielectric anisotropy Δε and are easy to synthesize. In particular, by reducing the rotational viscosity significantly lower switching times should be realized.

Surprisingly, it has been found that the dioxane derivatives according to the invention are excellent as component (s) of liquid-crystalline media are suitable. With their help, it is possible to obtain stable, liquid-crystalline media, in particular suitable for TFT or STN displays.

By suitable choice of the ring members and / or the terminal substituents, the physical properties of the dioxane derivatives according to the invention can be varied within wide limits. Thus, it is possible, for example, to obtain dioxane derivatives according to the invention having very small values of optical anisotropy or having low positive to high positive values of dielectric anisotropy.

In particular, the dioxane derivatives according to the invention are distinguished both by low optical anisotropy values and by unexpectedly low rotational viscosities.

Liquid crystalline media with very low levels of optical anisotropy are particularly important for reflective and transflective applications, i. Such applications in which the respective LCD experiences no or only supportive backlight.

With the provision of the dioxane derivatives according to the invention, the range of liquid-crystalline substances which are suitable for the preparation of liquid-crystalline mixtures from a variety of application-technical points of view is considerably broader.

The dioxane derivatives of the invention have a broad

Scope of application. Depending on the choice of substituents, these compounds may serve as base materials from which liquid crystalline media are predominantly composed. However, it is also possible to add liquid-crystalline base materials from other classes of compounds to the dioxane derivatives according to the invention in order, for example, to influence the dielectric and / or optical anisotropy of such a dielectric and / or to optimize its threshold voltage and / or its viscosity.

The dioxane derivatives according to the invention are colorless in the pure state. Chemically, thermally and against light, they are stable. The present invention thus relates to dioxane derivatives of the formula I.

R ¹ - (A ¹ -Z ¹ ) -G- (Z ² -A ² ) _n -R ²

wherein

R ¹ , R ^{2 are} each independently, identically or differently H, halogen (F, Cl, Br, I) or a linear or branched, optionally chiral, unsubstituted, mono- or polysubstituted by halogen alkyl or alkoxy radical having 1 to 15 C atoms in which one or more CH ₂ groups are each independently denoted by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-, - CH = CH-, -CH = CF-, -CF = CF-,

-C≡C- or ^~~ \ / ^{~ can} be replaced so that

Heteroatoms are not directly linked to each other, -CN, -SCN, -NCS, -SF ₅ , -SCF ₃ , -CF ₃ , -CF = CF ₂ , -CF ₂ CF ₂ CF ₃ , -OCF ₃ , -OCHF ₂ , -CF ₂ CH ₂ CF ₃ or -OCH ₂ CF ₂ CHFCF ₃ ,

A ¹ , A ^{2 are} each independently, the same or different

a) trans-1,4-cyclohexylene, in which also one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S- and in which also one or more H atoms may be replaced by F, b) 1,4-phenylene, in which one or two CH groups may be replaced by N and in which also one or more H atoms are represented by halogen (F, Cl, Br, I), -CN, -CH ₃ , -CHF ₂ , -CH ₂ F, -CF ₃ , -OCH ₃ , -OCHF ₂ or -OCF ₃ may be replaced,

c) a radical from the group of bicyclo [1.1.1] pentane-1,3-diyl, bicyclo [2.2.2] octane-1,4-diyl, spiro [3.3] heptane-2,6-diyl, naphthalene 2,6-diyl, naphthalene-2,7-diyl, decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene

2,6-diyl, piperidine-1,4-diyl, phenanthrene-2,7-diyl, fluoren-2,7-diyl, anthracene-2,6-diyl, anthracene-2,7-diyl and indan-2, 5-diyl, where an H atom or several H atoms can be replaced by halogen, in particular F,

d) 1,4-cyclohexenylene or cyclobutane-1,3-diyl,

Each of Z ¹ , Z ² is independently, identically or differently -O-, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -CF ₂ O-, -OCF ₂ -, -CF ₂ CF ₂ -,

-CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CH ₂ -, -CH = CH-, -CH = CF-, -CF = CH-, -CF = CF-, -CF = CF- COO, -O-CO-CF = CF-, -C≡C-, -CH ₂ CH ₂ CF ₂ O- or a single bond, and

m, n are independently, identically or differently O, 1, 2 or 3, preferably m = 0, 1 or 2 and n = 1 or 2, more preferably m = 0 or 1 and n = 1 or 2, and especially m = O and n = 1 or 2,

mean.

Another object of the present invention is the use of compounds of formula I as component (s) in liquid-crystalline media. Likewise provided by the present invention are liquid-crystalline media having at least two liquid-crystalline components which contain at least one compound of the formula I.

The subject of the present invention is also liquid crystal

Display elements, in particular electro-optical display elements, which contain a liquid crystalline medium according to the invention as a dielectric.

Particularly preferred are reflective and transflective liquid crystal display elements and other low birefringence liquid crystal displays .DELTA.n, so-called "low Δn mode displays", such. reflective and transflective TN displays.

The meaning of the formula I includes all isotopes of the chemical elements bound in the compounds of the formula I. In enantiomerically pure or enriched form, the compounds of the formula I are also suitable as chiral dopants and generally for the achievement of chiral mesophases.

Above and below, R ¹ , R ² , A ¹ , A ² , Z ¹ , Z ² , G, m and n have the meaning given, unless expressly stated otherwise. If the radicals A ¹ and A ² or Z ¹ and Z ² more than once, so they can assume independently of one another identical or different meanings.

Preferred compounds of the formula I are compounds of the partial formula Ia

Ia

and compounds of sub-formula Ib

wherein R ¹ , R ² , A ¹ , A ² , Z ¹ , Z ² , m and n have the meanings given above.

Preference is given to compounds of the formula I in which R ^{1 is} H or a linear alkyl radical having 1 to 10 C atoms.

Preference is likewise given to compounds of the formula I in which R ^{2 is} H, a linear alkoxy radical having 1 to 10 C atoms, -F, -Cl, -CF ₃ , -OCF ₃ , -OCHF ₂ , -CN, -NCS or -SF ₅ , more preferably -F, -CF ₃ , -OCF ₃ or -CN.

Z ¹ is preferably -CH ₂ CH ₂ -, -CH = CH-, -G≡C-, -CF ₂ CF ₂ -,

-CF = CF-, -CF ₂ O-, -OCF ₂ - or a single bond, more preferably a single bond.

Z ² is preferably -CH ₂ CH ₂ -, -CH = CH-, -C≡C-, -CF ₂ CF ₂ -,

-CF = CF-, -CF ₂ O-, -OCF ₂ - or a single bond, more preferably -CF ₂ O- or a single bond.

For the sake of simplicity, Cyc denotes a 1,4-cyclohexylene radical, Che denotes a 1,4-cyclohexenylene radical, Dio denotes a 1,3-dioxane-2,5-diyl radical, and denotes a 1,3-dithiane-2,5-diol radical. diyl radical, Phe a 1,4-phenylene radical, Pyd a pyridine-2,5-diyl radical, Pyr a pyrimidine-2,5-diyl radical, Bco a bicyclo- (2,2,2) -octylene radical, Dec a decahydronaphthalene-2, 6-diyl, Nap is a naphthalene-2,6-diyl or naphthalene-2,7-diyl radical, Thn is a 1 ^ .S ^ -tetrahydronaphthalene ^... O-diyl radical, pip is a piperidine-1, 4-diyl radical, Phe is a Phenanthrene-2,7-diyl, Flu is a fluorene-2,7-diyl, Ant is an anthracene-2,6-diyl or anthracene-2,7-diyl and Ind is an indan-2,5-diyl, wherein Cyc and or Phe can be unsubstituted or monosubstituted or polysubstituted by CH ₃ , Cl, F or CN. A ¹ and A ^{2 are} preferably Phe, Cyc, Che, Pyd, Pyr or Dio, and particularly preferably Phe or Cyc.

Phe is preferable

The terms 1, 3-dioxane-2,5-diyl and Dio each include the two positional isomers

The cyclohexene-1,4-diyl group preferably has the following structures:

Particularly preferred compounds of formula Ia include the following formulas:

wherein R ¹ and R ^{2 have} the meanings given above and L ¹ , L ² ,

LL ³³ and LL ⁴⁴ L independently of one another, identically or differently, denote H or F.

Particularly preferred compounds of formula Ib include the following formulas:

wherein R ¹ and R ^{2 have} the meanings given above and L ¹ , L ² , L ³ and L ⁴ independently, identically or differently mean H or F.

Preference is given to compounds of the formulas Iaa to Iaf and Iba to Ibh in which R ^{1 is} H or a linear alkyl or alkoxy radical having 1 to 10 C atoms or alkenyl or alkenyloxy having 2 to 10 C atoms.

Likewise preferred are compounds of the formulas Iaa to Iaf and Iba to Ibh, in which R ^{2 is} -F, -CF ₃ , -OCF ₃ or -CN.

Particular preference is given to compounds of the formulas Iaa to Iaf and Iba to Ibh in which R ^{2 is} -F, -CF ₃ , -OCF ₃ or -CN, L ¹ , L ² , L ³ and L ⁴ independently of one another, identical or different or H mean.

Especially preferred are compounds of the formula Iaa and lac. They include in particular the following formulas:

Iaa2 - I cJ -

wherein R ^{1 has} the meaning given above.

Particular preference is furthermore given to compounds of the formula Iba and Ibd. They include in particular the following formulas:

- -

Ibd1

35

wherein R ^{1 has} the meaning given above.

Preference is given to compounds of the formulas Iaa1 to Iaa9, Lad to Iac9, Iba1 to Iba9 and Ibd1 to Ibd9, in which R ^{1 is} H or a linear alkyl or alkoxy radical having 1 to 10 C atoms or alkenyl or alkenyloxy having 2 to 10 C -Atomen, more preferably a linear alkyl radical having 1 to 10 carbon atoms, means.

If R ¹ and / or R ² in the above and following formulas denotes an alkyl radical, this may be straight-chain or branched. It is particularly preferably straight-chain, has 2, 3, 4, 5, 6 or 7 carbon atoms and thus means ethyl, propyl, butyl, pentyl, hexyl or heptyl, furthermore methyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl , Tetradecyl or pentadecyl.

If R ¹ and / or R ^{2 is} an alkyl radical in which a Chfe group is replaced by -O-, this may be straight-chain or branched. It is preferably straight-chain and has 1 to 10 C atoms. Particularly preferably, the first Ch ^ group of this alkyl radical is replaced by -O-, so that the radical R ¹ and / or R ^{2 is} alkoxy and in particular methoxy, ethoxy, propoxy, butoxy, pentyloxy, hexyloxy, heptyloxy, octyloxy or Nonyloxy means.

Furthermore, a CH 2 group can also be replaced elsewhere by -O-, so that the radical R ¹ and / or R ^{2 is} preferably straight-chain 2-oxa propyl (= methoxymethyl), 2- (= ethoxymethyl) or 3-oxabutyl (= 2-methoxyethyl), 2-, 3- or 4-oxapentyl, 2-, 3-, A- or 5-oxahexyl, 2-, 3 -, 4-, 5- or 6-oxaheptyl, 2-, 3-, 4-, 5-, 6- or 7-oxaoctyl, 2-, 3-, 4-, 5-, 6-, 7- or 8 -Oxanonyl, 2-, 3-, 4-, 5-, 6-, 7-, 8- or 9-oxadecyl.

If R ¹ and / or R ^{2 is} an alkyl radical in which one CH ₂ group has been replaced by -CH = CH-, this may be straight-chain or branched. It is preferably straight-chain and has 2 to 10 C atoms. It therefore means vinyl, prop-1 or prop-2-enyl, but-1, 2- or but-3-enyl, pent-1, 2-, 3- or pent-4-enyl, hex-1 -, 2-, 3-, 4- or hex-5-enyl, hept-1, 2-, 3-, A-, 5- or hept-6-enyl, Oct-1, 2-, 3- , 4-, 5-, 6- or oct-7-enyl, non-1-, 2-, 3-, 4-, 5-, 6-, 7- or non-8-enyl, Dec-1-, 2-, 3-, A-, 5-, 6-, 7-, 8- or dec-9-enyl.

Preferred alkenyl groups are C ₂ -C ₇ -I E-alkenyl, C ₄ -C ₇ -EE-alkenyl,

C ₅ -C ₇ alkenyl, C ₆ -C ₇ -5 alkenyl, and C ₇ -C ₆ alkenyl, more preferably C ₂ -C ₇ -I E-alkenyl, C ₄ -C ₇ 3E-alkenyl and C ₅ -C ₇ -4 alkenyl.

Examples of particularly preferred alkenyl groups are vinyl, 1E-propenyl, 1E-butenyl, 1E-pentenyl, 1E-hexenyl, 1E-heptenyl, 3-butenyl, 3E-pentenyl, 3E-hexenyl, 3E-heptenyl, 4-pentenyl, 4Z Hexenyl, 4E-hexenyl, 4Z-heptenyl, 5-hexenyl and 6-heptenyl. Groups of up to 5 carbon atoms are especially preferred.

If R ¹ and / or R ^{2 is} an alkyl radical in which one CH ₂ group has been replaced by -O- and one by -CO-, these are preferably adjacent. Thus, these include an acyloxy group -CO-O- or an oxycarbonyl group -O-CO-. These are particularly preferably straight-chain and have 2 to 6 C atoms.

Accordingly, they particularly mean acetyloxy, propionyloxy, butyryloxy, pentanoyloxy, hexanoyloxy, acetyloxymethyl, propionyloxymethyl, butyryloxymethyl, pentanoyloxymethyl, 2-acetyloxyethyl, 2-propionyl-oxyethyl, 2-butyryloxyethyl, 3-acetyloxypropyl, 3-propionyloxypropyl, 4-acetyloxybutyl, methoxycarbonyl, Ethoxycarbonyl, propoxycarbonyl, butoxycarbonyl, pentoxycarbonyl, methoxycarbonylmethyl, ethoxy ""

- I o -

carbonylmethyl, propoxycarbonylmethyl, butoxycarbonylmethyl, 2- (methoxycarbonyl) ethyl, 2- (ethoxycarbonyl) ethyl, 2- (propoxycarbonyl) ethyl, 3- (methoxycarbonyl) propyl, 3- (ethoxycarbonyl) propyl and 4- (methoxycarbonyl) butyl.

If R ¹ and / or R ^{2 is} an alkyl radical in which one CH ₂ group is unsubstituted or substituted -CH = CH- and one adjacent CH ₂ group is -CO-, -CO-O- or -O-CO - Is replaced, it may be straight-chain or branched. Preferably, it is straight-chain and has 4 to 13 carbon atoms. It therefore particularly preferably means acryloyloxymethyl, 2-acryloyloxyethyl, 3-acryloyloxypropyl, 4-acryloyloxybutyl, 5-acryloyloxypentyl, 6-acryloyloxyhexyl, 7-acryloyloxyheptyl, 8-acryloyloxyoctyl, 9-acryloyloxynonyl, 10-acryloyloxydecyl, methacryloyloxymethyl, 2-methacryloyloxyethyl, 3 Methacryloyloxypropyl, 4-methacryloyloxybutyl, 5-methacryloyloxypentyl, 6-methacryloyloxyhexyl, 7-methacryloyloxyheptyl, 8-methacryloyloxyoctyl and 9-methacryloyloxynonyl.

If R ¹ and / or R ² is a monosubstituted by CN or CF ₃ alkyl or alkenyl radical, this radical is preferably straight-chain and the substitution by CN or CF ₃ in ω-position.

If R ¹ and / or R ^{2 is} an alkyl radical which is at least monosubstituted by halogen, this radical is preferably straight-chain. Halogen is preferably F or Cl. In the case of multiple substitution, halogen is preferably F. The resulting radicals also include perfluorinated radicals. For single substitution, the fluoro or chloro substituent may be in any position, but preferably in the ω position.

Compounds of the formula I with branched wing group R ¹ and / or R ² may occasionally be of importance because of a better solubility in the customary, liquid-crystalline base materials, but in particular as chiral dopants, if they are optically active. Smectic compounds of this type are useful as components of ferroelectric materials. " _N

- I y -

Branched groups of this type usually contain no more than one chain branch. Preferred branched radicals R ¹ and / or R ² are isopropyl, 2-butyl (= 1-methylpropyl), isobutyl (= 2-methylpropyl), 2-methylbutyl, isopentyl (= 3-methylbutyl), 2-methylpentyl, 3-methylpentyl , 2-ethylhexyl, 2-propylpentyl, isopropoxy, 2-methylpropoxy, 2-methylbutoxy, 3-methylbutoxy, 2-methylpentyloxy, 3-methylpentyloxy, 2-ethylhexyloxy, 1-methylhexyloxy and 1-methylheptyloxy.

Formula I comprises both the racemates of these compounds and the optical antipodes and mixtures thereof.

Among the compounds of the formula I and the sub-formulas, preference is given to those in which at least one of the radicals contained therein has one of the preferred meanings given.

The compounds of the formula I are prepared by methods known per se, as described in the literature (for example in the standard works, such as Houben-Weyl, Methods of Organic Chemistry, Georg-Thieme-Verlag, Stuttgart), specifically under reaction conditions suitable for the said reactions are known and suitable. One can make use of known per se, not mentioned here variants.

The compounds of formula I can e.g. be prepared according to the following reaction schemes or in analogy thereto. Further synthetic methods can be found in the examples.

Scheme 1:

Scheme 2:

Me ₃ SiOSO ₂ CF ₃

Scheme 3:

In Schemes 1 to 3, R ¹ , R ² , A ¹ , A ² , Z ¹ , Z ² , m and n are as defined above.

The present invention also relates to the in

Schemes 1 and 2 used as starting materials spiro-diols of the following formula

wherein R ¹ , A ¹ , Z ¹ and m have the meanings given in relation to formula I.

The other starting materials are either known or can be used in

Be prepared analogously to known compounds.

Optionally, the starting materials can also be formed in situ, such that they are not isolated from the reaction mixture, but immediately further reacted to the compounds of formula I.

The liquid-crystalline media according to the invention preferably contain, in addition to one or more compounds according to the invention, as further constituents 2 to 40, particularly preferably 4 to 30 components. In particular, these media contain, in addition to one or more compounds according to the invention 7 to 25 components. These further constituents are preferably selected from nematic or nematogenic (monotropic or isotropic) substances, in particular substances from the classes of azoxybenzenes, benzylideneanilines, biphenyls, terphenyls, phenyl or cyclohexyl benzoates, cyclohexane-carboxylic acid phenyl or cyclohexyl esters, phenyl or cyclohexyl esters Cyclohexylbenzoic acid, phenyl or cyclohexyl esters of cyclohexylcyclohexanecarboxylic acid, cyclohexylphenyl esters of benzoic acid, cyclohexanecarboxylic acid or cyclohexylcyclohexanecarboxylic acid, phenylcyclohexanes, cyclohexylbiphenyls, phenylcyclohexylcyclohexanes, cyclohexylcyclohexanes, cyclohexylcyclohexylcyclohexenes, 1,4-biscyclohexylbenzenes, 4,4'-biscyclohexylbiphenyls , Phenyl- or cyclohexylpyrimidines, phenyl- or cyclohexylpyridines, phenyl- or cyclohexyl-dioxanes, phenyl- or cyclohexyl-1,3-dithiane, 1,2-diphenylethane, 1,2-dicyclohexylethane, 1-phenyl-2-cyclohexylethane , 1-Cyclohexyl-2- (4-phenylcyclohexyl) - ethane, 1-cyclohexyl-2-biphenylylethane, 1-phenyl-2-cyclohexyl-phenylethane, optionally halogenated stilbenes, benzyl phenyl ethers, tolans and substituted cinnamic acids. The 1,4-phenylene groups in these compounds may also be fluorinated. The most important compounds which may be used as further constituents of the media according to the invention can be characterized by the formulas 1, 2, 3, 4 and 5:

R'-L-E-R "1

R'-L-COO-E-R "2

R'-L-OOC-E-R "3

R ^ L-CH ₂ CH ₂ -ER "4

R'-L-C≡C-E-R "5

In formulas 1, 2, 3, 4 and 5, L and E, which may be the same or different, each independently represents a bivalent radical selected from the group consisting of -Phe-, -Cyc-, -Phe-Phe-, -Phe- Cyc, -Cyc-Cyc, -Pyr-, -Dio, -G-Phe- and -G-Cyc- and their mirror images formed group, wherein Phe is unsubstituted or substituted by fluorine 1, 4-phenylene, cyc trans- 1,4-cyclohexylene or 1,4-cyclohexenylene, Pyr pyrimidine-2,5-diyl or pyridine-2,5-diyl, dio 1, 3-dioxane-2,5-diyl and G 2- (trans-1, 4-cyclohexyl) -ethyl.

Preferably, one of L and E is Cyc, Phe or Pyr. E is preferably Cyc, Phe or Phe-Cyc. The media according to the invention preferably comprise one or more components selected from the compounds of the formulas 1, 2, 3, 4 and 5, in which L and E are selected from the group Cyc, Phe and Pyr and simultaneously one or more components selected from the compounds of the Formulas 1, 2, 3, 4 and 5, wherein one of the radicals L and E is selected from the group Cyc, Phe and Pyr and the other radical is selected from the group -Phe- Phe-, -Phe-Cyc-, - Cyc-Cyc, -G-Phe and -G-Cyc-, and optionally one or more components selected from the compounds of formulas 1, 2, 3, 4 and 5, wherein the radicals L and E are selected from the group -Phe-Cyc, -Cyc-Cyc, -G-Phe and -G-Cyc-.

R ¹ and / or R "are each independently of one another alkyl, alkenyl, alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy having up to 8 C atoms, -F, -Cl, -CN, -NCS, - (O) iCH _{3- ( k +} i) F _k Cl, where i is 0 or 1, k and I are independent are equal to or different from 0, 1, 2 or 3 and for the sum (k + I): 1 <(k + I) <3.

R ¹ and R "in a smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5 in each case independently of one another are alkyl, alkenyl,

Alkoxy, alkoxyalkyl, alkenyloxy or alkanoyloxy with up to 8 carbon atoms. In the following, this smaller subgroup will be called Group A and the compounds will be referred to as Partial Formulas 1a, 2a, 3a, 4a and 5a. In most of these compounds, R ¹ and R "are different from one another, one of these radicals usually being alkyl, alkenyl, alkoxy or alkoxyalkyl.

In a smaller subgroup of compounds of formulas 1, 2, 3, 4 and 5, other than group B, R "is -F, -Cl, -NCS or - (O) j CH3 - _{(k +} i ₎ F _k Cl | where i is 0 or 1, k and I are independently, identically or differently 0, 1, 2 or 3 and for the sum (k + I): 1 <(k + I) <3. The compounds in which R "has this meaning, are denoted by the subformulae 1 b, 2b, 3b, 4b and 5b. Particular preference is given to those compounds of the subformulae 1b, 2b, 3b, 4b and 5b in which R "has the meaning -F, -Cl, -NCS, -CF ₃ , -OCHF ₂ or -OCF ₃ .

In the compounds of sub-formulas 1b, 2b, 3b, 4b and 5b, R ^{1 has} the meaning given for the compounds of sub-formulas 1a to 5a and is preferably alkyl, alkenyl, alkoxy or alkoxyalkyl.

In a further smaller subgroup of the compounds of the formulas 1, 2, 3, 4 and 5, R "denotes -CN. This subgroup is referred to below as group C and the compounds of this subgroup are correspondingly reacted with partial formulas 1c, 2c, 3c, 4c and In the compounds of sub-formulas 1c, 2c, 3c, 4c and 5c, R ^{1 has} the meaning given for the compounds of sub-formulas 1a to 5a and is preferably alkyl, alkoxy or alkenyl.

In addition to the preferred compounds of groups A, B and C are also other compounds of formulas 1, 2, 3, 4 and 5 with other variants the proposed substituents in use. All these substances are available by literature methods or by analogy.

In addition to compounds of the formula I according to the invention, the media according to the invention preferably comprise one or more compounds which are selected from groups A, B and / or C. The mass fractions of the compounds from these groups on the media according to the invention are preferably:

Group A: preferably 0 to 90%, particularly preferably 20 to 90%, in particular 30 to 90%;

Group B: preferably 0 to 80%, particularly preferably 10 to 80%, in particular 10 to 65%;

Group C: preferably 0 to 80%, particularly preferably 5 to 80%, in particular 5 to 50%;

wherein the sum of the mass fractions of the compounds of the groups A, B and / or C contained in the respective inventive media is preferably 5 to 90% and particularly preferably 10 to 90%.

The media according to the invention preferably contain 1 to 40%, more preferably 5 to 30% of the compounds of the formula I. Further preferred are media containing more than 40%, particularly preferably 45 to 90% of compounds of the formula I. The media preferably three, four or five compounds according to the invention.

The preparation of the liquid-crystal mixtures according to the invention is carried out in a conventional manner. In general, the desired amount of the components used in lesser amount is dissolved in the components making up the main component, preferably at elevated temperature. It is also possible to use solutions of the components in an organic solvent, e.g. In acetone, chloroform or methanol _" , _

mix and remove the solvent after mixing again, for example by distillation. Furthermore, it is possible to use the mixtures in other conventional ways, for. B. by using premixes, for. B. homolog mixtures or using so-called "multi-bottle" systems to produce.

The dielectrics may also contain further additives known to the person skilled in the art and described in the literature. For example, 0 to 15%, preferably 0 to 10%, of pleochroic dyes and / or chiral dopants may be added. The individual, added

Compounds are preferably used in concentrations of from 0.01 to 6%, particularly preferably from 0.1 to 3%. However, the concentration data of the other constituents of the liquid-crystal mixtures ie the liquid-crystalline or mesogenic compounds are given, without taking into account the concentration of these additives.

The following examples are intended to illustrate the invention without limiting it. Above and below, percentages are by weight. All temperatures are in degrees Celsius. Mp means melting point and KIp. = Clearing point. Furthermore, K = crystalline

State, N = nematic phase, Sm = smectic phase and I = isotropic phase. The data between these symbols represent the transition temperatures. Δn means optical anisotropy (589 nm, 2O ⁰ C) and Δε the dielectric anisotropy (IkHz, 20 ⁰ C).

The Δn and Δε values of the compounds according to the invention are obtained by extrapolation from liquid-crystalline mixtures which consist of 10% of the particular compound according to the invention and 90% of the commercially available liquid crystal ZLI 4792 (Merck, Darmstadt).

"Conventional workup" means: water is optionally added, extracted with methylene chloride, diethyl ether or toluene, separated, the organic phase is dried, evaporated and the product is purified by distillation under reduced pressure or crystallization and / or chromatography. The following abbreviations are used above and below:

DCM dichloromethane

DMF dimethylformamide

MTB ether methyl tert-butyl ether

RT room temperature (about 20 ^° C.)

THF tetrahydrofuran

^

Examples

example 1

346 ml (3.00 mol) of 1-pentene are dissolved in 3 l of diethyl ether and admixed with 315 g (4.83 mol) of zinc and 15 g (80 mmol) of copper (II) acetate monohydrate. Subsequently, 370 ml (3.30 mol) of trichloroacetyl chloride are added dropwise to the mixture, wherein the reaction mixture begins to boil. After 24 hours at room temperature, the solids are separated and the filtrate is washed with water, concentrated and passed through silica gel

(Pentane / DCM 3: 2). This gives 365 g of a yellow oil (content: 64%).

7 8

430 mmol of chlorinated cyclobutanone 7 (10O g (content 77%)) are dissolved in 500 ml of acetic acid and treated portionwise with 100 g (1, 5 mol) of zinc, so that a temperature of 80 ⁰ C is not exceeded. When the addition is complete, the batch is kept at 80 ^° C. for a further 2 hours. After cooling to room temperature, the mixture is stirred with 500 ml of water and extracted with MTB ether. The combined organic phases are washed with water and saturated sodium bicarbonate solution washed, dried over sodium sulfate and concentrated. This gives 45.1 g of a yellow oil (content 78.7%).

10

930 g (2.6 mol) of the Wittig salt 10 and 292 g of the ketone 8 are suspended in 2.5 l of THF and treated at a temperature below 2O ⁰ C in portions with 292 g (2.6 mol) of potassium tert. butoxide added. The mixture is stirred overnight at room temperature. After the addition of water, it is acidified with hydrochloric acid and extracted with n-pentane. The organic phase is concentrated and filtered through silica gel with n-pentane. This gives 100.7 g (content 30%) of a yellow liquid.

11

Analogously to the above procedure, the ketone 11 is prepared.

11 12

Analogously to the above procedure, dechlorination to ketone 12 is carried out.

100 ml of THF and 300 ml of dichloromethane are mixed at a temperature of -1O ⁰ C to -2 ° C with 30.0 ml (273 mmol) of titanium tetrachloride. Subsequently, at -1O ⁰ C 22.8 ml (150 mmol) of diethyl malonate (13) and 24.0 g (95%, 150 mmol) of the ketone 12 added in the reaction solution. At a temperature below -5 ° C, 44.0 ml (546 mmol) of pyridine are added dropwise to the reaction. After 18 hours at room temperature, the reaction mixture is mixed with 1500 ml of water. The organic phase is washed with water and concentrated. The residue is filtered through silica gel (toluene / MTB ether 9: 1). This gives 45.3 g (89%, 91%) of the ester 14.

45.3 g (90%, 140 mmol) of the diester 14 is hydrogenated in THF on the palladium catalyst. The catalyst is separated off and the solution is concentrated. The residue obtained is used without further purification in the next step. 44.4 g (92%) of the saturated ester 15 are obtained.

LiAlH.

17 Under nitrogen, a suspension of 6.3 g (170 mmol) of lithium aluminum hydride in 100 ml of THF is treated with a solution of 44.4 g (150 mmol) of the diester 15 in 100 ml of THF. This warms the approach to boiling. After completion of the addition, the approach for 1 hour under

Reflux heated. At room temperature, the approach is careful with

Hydrolyzed water and hydrochloric acid. The reaction mixture is filtered through Celite. The organic phase is washed with water and saturated sodium bicarbonate solution and concentrated. This gives 32.1 g (content 77.4%) of the diol 17th

8.0 g (77.4%, 29.1 mmol) of diol 17 and 9.0 g (132 mmol) of imidazole are dissolved in 60 ml of DMF under nitrogen and treated with 11.4 ml (90.0 mmol).

Added chlorotrimethylsilane and stirred overnight. The approach is with

Water and extracted with MTB ether. The organic phase is concentrated and the residue is purified on silica gel. 5.5 g (90%) of the silyl ether 18 are obtained.

Synthesis path a), R = H:

16.0 g (77.4%, 58.3 mmol) of the diol 17 and 9.3 g (58.0 mmol) of the aldehyde 19 are dissolved in 100 ml of toluene, with 400 mg of p-toluenesulfonic acid (p -TsOH) and heated under reflux at the water. The mixture is then washed with water and saturated sodium bicarbonate solution, concentrated and purified over silica gel "O l *

(Toluene / heptane). The product obtained is crystallized from heptane. This gives 5.7 g of dioxane 20 as colorless crystals of melting point 58 ⁰ C.

Synthesis path b), R = SiMO ₃ :

Under nitrogen, a solution of 5.0 g (14.2 mmol) of the disilyl ether 18 in 60 ml of dichloromethane at -78 ° C with 0.4 ml (2.1 mmol) of trimethylsilyl trifluoromethanesulfonat added. Subsequently, a solution of 3.2 g (20.0 mmol) of the aldehyde 19 is added dropwise. After 2 hours at the low temperature, 2.0 ml of pyridine are added and the cooling is removed. After addition of 70 ml of saturated sodium bicarbonate solution, the aqueous phase is extracted with dichloromethane, the combined organic phases are dried over sodium sulfate and concentrated. The further purification is carried out in the manner described in synthesis route a). 3.2 g (64%) of compound 20 are obtained.

K 58 I ₁ Δε = 13.9 and Δn = 0.0615.

Analogously to Example 1 using the appropriate

Precursors obtained the following compounds of the invention:

Examples 2-18

Examples 19-36

Examples 37-54

Examples 55-72

Analogously to Example 1, the following compound according to the invention is obtained using the corresponding precursor:

Example 73

K 66 N (63.4) I, Δ∈ = 24.3 and Δn = 0.0797.

Analogously to Example 73, the following compounds according to the invention are obtained using the appropriate precursors:

Examples 74-90

lac Examples 91-108

Examples 109-126

Examples 127-144

Examples R ¹ L ¹ L ²

82. 100. 118. 136. C _δ Hn HH

83. 101. 119. 137. C5H11 H F

84. 102. 120. 138. C5H11 F F

85. 103. 121. 139. CβHi3 H H

86. 104. 122. 140. CθHi3 H F

87. 105. 123. 141. C6H13 F F

88. 106. 124. 142. C7H15 H H

89. 107. 125. 143. C7H ₁ 5 HF

90. 108. 126. 144. C7H15 F F

For Examples 78 and 109, the following properties are determined:

Table 1

Example 145

Under nitrogen, the corresponding Grignard reagent is prepared in 75 ml of THF from 3.2 g (130 mmol) of magnesium turnings and 15.5 ml (130 mmol) of the bromide 2. Subsequently, a solution of the ketone 1 in 25 ml of THF is added to the reagent. The batch is heated to boiling for 1 hour. The cooled mixture is hydrolyzed to pH 1 with hydrochloric acid adjusted and extracted with MTB ether. The organic phase is washed with saturated sodium bicarbonate solution and concentrated. The residue obtained is purified on silica gel (toluene). Yield: 22.0 g (68%)

3 ₄

Under nitrogen, 14.4 g (40.0 mmol) of the alcohol 3 are dissolved in 80 ml of dichloromethane and 17 ml of triethylamine and treated at 0 ⁰ C with 4.1 ml (53.4 mmol) of methanesulfonyl chloride (MsCl). The mixture is stirred overnight at room temperature. Subsequently, the

The reaction mixture was added to water and diluted with n-heptane. The organic phase is concentrated and the residue obtained is passed through silica gel. The residue is used without further purification in the subsequent stage.

4

5

13.9 g of the crude alkene 4 is dissolved in THF and hydrogenated on the palladium catalyst. The hydrogenation solution is concentrated and the residue obtained is purified on silica gel. Yield: 9.7 g (88%)

,

Under nitrogen, 9.6 g (44.4 mmol) of pyridinium chlorochromate (PCC), 1, 2 g of sodium acetate and 6 g Celite suspended in 50 ml of dichloromethane and with a solution 9.4 g (36.7 mmol) of the alcohol. 5 in 60 ml DCM added. After completion of the reaction, the solid is triturated and washed with DCM. The eluate is washed with 1 N sodium hydroxide solution and 2N hydrochloric acid and concentrated. The residue obtained is passed through silica gel. The residue is used without further purification in the subsequent stage.

6 7

The crude aldehyde 6 is dissolved in toluene, mixed with p-toluenesulfonic acid and heated to boiling on a water. The cooled mixture is washed with saturated sodium bicarbonate solution and concentrated. The residue obtained is purified on silica gel and by crystallization from n-heptane. Yield: (30%)

K 70 I, Δε = 14.3 and Δn = 0.0322.

Analogously to Example 145, the following compounds according to the invention are obtained using the appropriate precursors: Examples 146-162

Examples 163-180

Examples 181-198

Examples 199-216

Examples R ¹ L ¹ L ²

145. 163. 181. 199. C ₃ H ₇ FF

146. 164. 182. 200. C ₃ H ₇ HF

147. 165. 183. 201. C ₃ H ₇ HH Examples R ¹ L ¹ L ²

148. 166. 184. 202. C2H5 H H

149. 167. 185. 203. C ₂ H ₅ HF

150. 168. 186. 204. C2H5 F F

151. 169. 187. 205. C4H9 H H

152. 170. 188. 206. C4H9 H F

153. 171. 189. 207. C4H9 F F

154. 172. 190. 208. C5H11 H H

155. 173. 191. 209. C5H11 H F

156. 174. 192. 210. C5H11 F F

157. 175. 193. 211. CβHi3 H H

158. 176. 194. 212. CβHi3 H F

159. 177. 195. 213. CθHi3 F F

160. 178. 196. 214. C7H15 H H

161. 179. 197. 215. C7H15 H F

162. 180. 198. 216. C7H15 F F

The compound of Example 201 is obtained as follows.

THF

8th

24.8 g (85 mmol) of the enol ether 7, 10 g (85 mmol) of 2-propyl-1, 3-propanediol and 400 mg of p-toluenesulfonic acid are mixed with 100 ml of toluene and heated to boiling for 3 h on a water. The cooled batch is washed with sat. NaHCO ₃ -sol. washed and concentrated. The crystals forming in the residue are isolated.

3.7 g (9.8 mmol) of the bromide 8 and 1, 1 g (12.6 mmol) of copper cyanide are mixed with 15 ml of N-methylpyrrolidone and heated to 140 ⁰ C for 4 h. The cooled mixture is mixed with 100 ml of water and extracted with MTB ether. The organic phase is filtered, dried and concentrated. After crystallization from ethanol at -20 ⁰ C the final cleaning takes place mitttels HPLC.

The product has the following properties:

K 69 S _H (53) N 73.4 I, Δ∈ = 26.2 and Δn = 0.1120. Examples 217-234

Examples 235-252

Examples 253-270

Examples 271-288

Examples R ¹ L ¹ L ²

217. 235. 253. 271. C ₃ H ₇ FF

218. 236. 254. 272. C ₃ H ₇ HF

219. 237. 255. 273. C ₃ H ₇ HH

220. 238. 256. 274. C2H5 H H

221. 239. 257. 275. C ₂ H ₅ HF

222. 240. 258. 276. C ₂ H ₅ FF

223. 241. 259. 277. C4H9 H H

224. 242. 260. 278. C4H9 H F

225. 243. 261. 279. C4H9 F F

226. 244. 262. 280. C5H11 H H

227. 245. 263. 281. C5H11 H F

228. 246. 264. 282. C5H11 F F

229. 247. 265. 283. CβHi ₃ HH

230. 248. 266. 284. COHI ₃ HF

231. 249. 267. 285. CβHi ₃ FF

232. 250. 268. 286. C7H15 H H

233. 251. 269. 287. C7H15 H F

234. 252. 270. 288. C7H15 F F

Example 289

Analogously to Example 73, the following compound according to the invention is obtained using the corresponding precursor:

In detail, the synthesis is carried out as follows.

346 ml (3.00 mol) of 1-pentene are dissolved in 3 l of diethyl ether and treated with 315 g (4.83 mol) of zinc and 15 g (80 mmol) of copper (II) acetate monohydrate. Then 70 ml (3.30 mol) of trichloroacetyl chloride are added dropwise to the mixture, wherein the reaction mixture begins to boil., After 24 h at room temp. When the solids are separated and the filtrate is washed with water, concentrated and passed through silica gel (Pen / DCM 3: 2). This gives 365g of a yellow oil (content: 64%).

430 mmol of chlorinated cyclobutanone 7 (10O g (content 77%)) are dissolved in 500 ml of acetic acid and treated in portions with 100 g (1.5 mol) of zinc, so that a temperature of 8O ⁰ C is not exceeded. After complete addition, the mixture is kept for ² h at 80 ⁰ C. After cooling to room temp. The mixture is stirred with 500 ml of water and extracted with MTB ether. The combined organic phases are washed with water and sat. Sodium bicarbonate solution. washed over Dried sodium sulfate and concentrated. This gives 45.1 g of a yellow oil (content 78.7%).

930 g (2.6 mol) of the Wittig salt 10 and 292 g of the ketone 8 are suspended in 2.5 l of THF and treated at a temperature below 2O ⁰ C in portions with 292 g (2.6 mol) of potassium tert. butoxide added. The approach is overnight at room temp. touched. After the addition of water, it is acidified with hydrochloric acid and extracted with n-pentane. The organic phase is concentrated and filtered through silica gel with n-Petnan. This gives 100.7 g (content 30%) of a yellow liquid.

¹⁰

The ketone 10 is prepared analogously to the above procedure.

10

11

Analogously to the above procedure, the dechlorination to the ketone 11 is carried out.

In E.V. Dehmlow, S. Bueker Chem. Ber. 1993, 126, 2759-2764 describes vinyl acetate as starting material for the construction of a cyclobutyl ring. Thus, compounds of type 1 can be prepared via the described synthesis.

¹ H-NMR (CDCl ₃ , TMS): 7.33 (s, 5H, Ph-); 4.52 (s, 2H, Ph-CH ₂ -O); 3.46 (d, J = 6.5Hz, 2H, O-CH ₂ -cyclobutyl), 3.10 and 2.98 (2m, 4H, 1-H ₂ and 3-H ₂ ); 2.60 (m _c, 1 H 6-H); 2.29 and 2.06 (2m _c , 4H, 5-H ₂ and 7-H ₂ ).

200 ml of THF and 600 ml of dichloromethane are mixed at a temp. From -10 ⁰ C to -2 ° C with 37.5 ml (340mmol) of titanium tetrachloride. Subsequently - 40 -

at -10 ⁰ C 28.6 ml (190 mmol) of diethyl malonate (13) and 50.0 g (86.5%, 190 mmol) of the ketone 12 is added to the reaction solution. At a temp. Below -2 ° C, 55 ml (546 mmol) of pyridine are added dropwise to the batch. After 18 h at room temp. The reaction mixture is mixed with 1500 ml of water. The organic phase is washed with water and concentrated. The residue is filtered through silica gel (toluene / MTB ether 9: 1). 54.8 g (75%, 59%) of the ester 14 are obtained.

54.8 g (75% strength, 110 mmol) of the diester 14 are hydrogenated in THF over the palladium catalyst. The catalyst is separated off and the solution is concentrated. The residue obtained is used without further purification in the next step. 43.7 g (77% strength) of the saturated ester 15 are obtained.

30 g of PCC (140 mmol) and 30 g of Celite 545 are suspended in 300 ml of dichloromethane and treated at T <25 ° C with 43.2 g (77% strength, 120 mmol) of the alcohol 15 dissolved in 200 ml of dichloromethane. Of the

Batch is stirred overnight. The filtrate of the suspension is concentrated and the residue is passed through silica gel (n-pentane / MTB ether 4: 1 - 1: 1). The residue is used without further purification in the subsequent stage.

24.7 g (70 mmol) of methyl-triphenylphosphonium bromide are treated at ⁰ ° C. with a solution of 7.2 g (60 mmol) of potassium tert-butoxide in 50 ml of THF. After 15 min, 13.0 g (50 mmol) of the aldehyde 16 dissolved in 50 ml of THF are added at this temperature. After 18 h at RT, the batch is mixed with water and adjusted to pH 6 with 1N hydrochloric acid. The aqueous phase is extracted with MTB ether. The organic phase is washed with water, dried over sodium sulfate and concentrated. The residue is passed through silica gel (n-pentane / MTB ether 7: 3). The residue is used without further purification in the subsequent stage.

18

A boiling suspension of 2.9 g (80 mmol) of lithium aluminum hydride in 50 ml of THF is treated with a solution of 18 g (70% strength, 60 mmol) of malonate 17 in 50 ml of THF and then refluxed for 1 h. The cooled mixture is hydrolyzed, acidified and diluted with MTB ether and filtered with suction through Celite. The organic phase is washed with water and sat. NaHC03 soln. washed, dried and concentrated. The residue is used without further purification in the subsequent stage.

- 4y -

10 g (90% strength, 50 mmol) of the diol 18, 15.5 g (50 mmol) of the aldehyde 19 and 400 mg of p-toluenesulfonic acid are mixed with 60 ml of toluene and heated for 1 h on a water. The cooled mixture was passed through silica gel (toluene). The product obtained is crystallized from n-heptane.

The product has the following properties:

K 75 N (54 .3) I,

Δε = 22.3 and

Δn = 0.0964

For example 78

7.0 g (90% strength, 12 mmol) of the alkene 20 are dissolved in THF and hydrogenated on the palladium catalyst. The solution is then concentrated and the residue is passed through silica gel (toluene / n-heptane 1: 1). Further purification by crystallization from n-heptane. The product has the properties:

K 71 N (50.5) I ₁ Δ∈ = 23.9 and Δn = 0.0894. Example 290

As an example of a compound of the formula I having two nonpolar end groups (with both R ¹ and R ^{2 being} alkyl or alkenyl), the preparation of the following compound is described.

The precursor of the compound compound is obtained according to the following reaction scheme.

Br. Ph KOtBu THF

The further synthesis is carried out as follows.

25 g (106 mmol) of the ketone 6 and 67.2 g (196 mmol) Methoxymethytriphenylphosphonium chloride are suspended in 250 ml of THF and, at T <20 ⁰ C with 11, 9 g (106 mmol) of potassium-butoxide terf. and stirred at RT for 18 h. The approach is with ges. Ammonium chloride solution. and diluted with 500 ml of n-heptane. The organic phase is concentrated and the residue is passed through silica gel (n-heptane / toluene 1: 1). The product is reacted without further purification in the next stage.

HCOOH

16 g of the product of the precursor are dissolved in 60 ml of toluene and mixed with 36 ml of formic acid and stirred at RT for 18 h. The mixture is then added to 200 ml of water. The aqueous phase was extracted with MTB ether, the organic phase with sat. NaHCO ₃ -sol. washed and concentrated. The residue was used without further purification in the subsequent stage.

br 9 10 -J ₁

298 g (1.32 mol) of tin (II) chloride, 300 g (1.32 mol) of ethyl 4-bromocrotonate and 438 g (2.64 mol) of potassium iodide are introduced into 3 l of water and at T <35 ⁰ C with a 37% solution of formaldehyde in water. After 24 h, the batch is extracted with diethyl ether. The organic phase is concentrated and passed through silica gel (toluene, toluene / MTB ether 1: 1). The residue is distilled in vacuo, b.p.

70 ° C.

11 ¹²

208 g (24%, 346 mmol) of the ester 11 are dissolved in toluene and added to a boiling suspension of 12.4 g (330 mmol) of lithium aluminum hydride in 100 ml of toluene and 1200 ml of THF. After heating for 1 h

Reflux and subsequent cooling, the reaction was hydrolyzed and treated with a hot solution of 93.2 g of sodium bicarbonate decahydrate in 30 ml of water. After stirring for 30 minutes, the solid is separated off. The filtrate is concentrated. The residue is used without further purification in the subsequent stage.

12

13

4.1 g (80% strength, 32 mmol) of the diol 12, 16.6 g (50% strength, 31 mmol) of the aldehyde 8 and 360 mg of p-toluenesulfonic acid are mixed with 60 ml of toluene and 1 h the water to Boil boiling. The cooled mixture is passed through silica gel (toluene), the eluate is concentrated, the residue is crystallized from n-heptane, added via basic AIO _x (toluene / n-heptane 1: 1) and recrystallized from n-heptane.

The product has the properties:

K 40 S _B 121 I, Δ∈ = 0.8 and Δn = 0.0491.

Claims

claims

1. dioxane derivatives of the formula I.

R ¹ - (A ¹ -Z ¹ ) -G (Z ² -A ² ) _n -R ²

wherein

R ¹ , R ^{2 are} each independently, identically or differently H, halogen (F, Cl, Br, I) or a linear or branched, optionally chiral, unsubstituted, mono- or polysubstituted by halogen alkyl or alkoxy radical having 1 to 15 C atoms in which also one or more CH ₂ groups are each independently of one another by -O-, -S-, -CO-, -CO-O-, -O-CO-, -O-CO-O-,

-CH = CH-, -CH = CF-, -CF = CF-, -C≡C- or - <V can be replaced so that heteroatoms are not directly linked, -CN, -SCN, -NCS, - SF ₅ , -SCF ₃ , -CF ₃ , -CF = CF ₂ , -CF ₂ CF ₂ CF ₃ , -OCF ₃ , -OCHF ₂ , -CF ₂ CH ₂ CF ₃ or -OCH ₂ CF ₂ CHFCF ₃ ,

A ¹ , A ^{2 are} each independently, the same or different

a) trans-1,4-cyclohexylene, in which also one or more non-adjacent CH ₂ groups may be replaced by -O- and / or -S- and in which also one or more H atoms may be replaced by F, b) 1,4-phenylene, in which one or two CH groups may be replaced by N and in which also one or more H atoms are represented by halogen (F, Cl, Br, I), -CN, -CH ₃ , -CHF ₂ , -CH ₂ F, CF ₃ , -OCH ₃ , -OCHF ₂ or

-OCF ₃ can be replaced,

c) a radical from the group of bicyclo [1.1.1] pentane-1,3-diyl, bicyclo [2,2,2] octane-1,4-diyl, spiro [3.3] heptane-2,6-diyl, naphthalene 2,6-diyl, naphthalene-2,7-diyl,

Decahydronaphthalene-2,6-diyl, 1,2,3,4-tetrahydronaphthalene-2,6-diyl, piperidine-1,4-diyl, phenanthrene-2,7-diyl, fluorene-2,7-diyl, anthracene 2,6-diyl, anthracene-2,7-diyl and indane-2,5-diyl, where one or more H atoms can be replaced by halogen, in particular F,

d) 1,4-cyclohexenylene or 1,3-cyclobutane-1,3-diyl,

Z ¹ , Z ^{2 are} each independently, the same or different

-O-, -CH ₂ O-, -OCH ₂ -, -CO-O-, -O-CO-, -CF ₂ O-, -OCF ₂ -, -CF ₂ CF ₂ -, -CH ₂ CF ₂ -, -CF ₂ CH ₂ -, -CH ₂ CH ₂ -, -CH = CH-, -CH = CF-, -CF = CH-, -CF = CF-, -CF = CF-COO-, -0 -CO-CF = CF-, -C≡C-, -CH ₂ CH ₂ CF ₂ O- or a single bond, and

m, n independently of one another, the same or different O, 1, 2 or 3,

mean.

2. Compounds according to claim 1, characterized in that m

= O, 1 or 2 and n = 1 or 2.

3. Compounds according to claim 1 or 2, characterized in that m = 0 or 1 and n = 1 or 2.

4. Compounds according to one or more of claims 1 to 3, characterized in that G

means.

5. Compounds according to one or more of claims 1 to 4, characterized in that G

means.

6. Compounds according to one or more of claims 1 to 5, characterized in that they have one of the following formulas:

wherein R ¹ and R ^{2 have} the meanings given in claim 1 and L ¹ , L ² , L ³ and L ⁴ independently, identically or differently mean H or F.

7. Compounds according to one or more of claims 1 to 6, characterized in that they have one of the following formulas:

35

8. Compounds according to at least one or more of

Claims 1 to 7, characterized in that R ^{1 is} H or a linear alkyl radical having 1 to 10 carbon atoms.

9. Compounds according to at least one or more of claims 1 to 8, characterized in that R ^{2 is} H, a linear alkoxy radical having 1 to 10 C atoms, -F, -Cl, -CF ₃ , -OCF ₃ , -

OCHF ₂ , -CN, -NCS or -SF ₅ means.

10. Use of compounds of the formula I according to one or more of claims 1 to 9 as component (s) in liquid-crystalline media.

11. Liquid-crystalline medium having at least two liquid-crystalline components, characterized in that it contains at least one compound of the formula I according to one or more of claims 1 to 9.

12. Liquid crystal display element, characterized in that it contains a liquid-crystalline medium according to claim 11.

13. Reflective or transflective liquid crystal display element, characterized in that it contains a liquid-crystalline medium according to claim 11.

14. Electro-optical display element, characterized in that it contains a liquid-crystalline medium according to claim 11.

15. Spiro-diols of the following formula

1 1 1 wherein R ₁ A ₁ Z and m have the meanings given in relation to formula I in claim 1.

16. A process for preparing a compound of the formula I according to one or more of Ansprücghe 1 to 9, characterized in that a spiro-diol is used according to claim 15.