New entry for fluorinated carbocycles: Unprecedented 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane derivatives

Yamada, Shigeyuki; Hashishita, Shohei; Konishi, Hide A.; Nishi, Yuji; Kubota, Toshio; Asai, Tomoyuki; Ishihara, Takashi; Konno, Tsutomu

doi:10.1016/j.jfluchem.2017.05.013

Cited by 17 publications

(11 citation statements)

References 65 publications

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“…Compound 3a could be converted to the cyclohexadiene 1a in 82% isolated yield under the influence of a large amount of phosphorus oxychloride in pyridine at 90 °C for 1 d according to the previous literature [ 12 ]. On the other hand, 4a could also be transformed into the corresponding bisxanthate derivative 9a according to the literature procedure [ 13 ]. Without further purification, 9a was treated with 4.0 equiv of n -Bu 3 SnH and 2.0 equiv of Et 3 B in dichloromethane at room temperature for 1 d to afford the desired reduction products 2a as an inseparable diastereomeric mixture in a trans / cis ratio of ca.…”

Section: Resultsmentioning

confidence: 99%

“…In fact, as shown in Fig. 1 , tricyclic molecules containing a CF 2 CF 2 carbocycle, e.g., the 5,5,6,6-tetrafluorocyclohexa-1,3-diene [ 12 ] or the 1,1,2,2-tetrafluorocyclohexane motif [ 13 ], were successfully synthesized and found to exhibit a large negative Δε value (−7.3 for 1c and −9.4 for trans - 2c ) [ 14 ]. This indicated that these compounds are promising candidates for vertical alignment (VA)-type display materials.…”

Section: Introductionmentioning

confidence: 99%

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Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

Kumon

Hashishita

Kida

et al. 2018

Beilstein J. Org. Chem.

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Herein, we demonstrate an improved short-step protocol for the synthesis of multicyclic molecules having a CF2CF2-containing cyclohexadiene or cyclohexane framework in a mesogenic structure. These molecules are promising candidates for vertical alignment (VA)-mode liquid crystal (LC) display devices owing to their large negative dielectric constant. The tetrafluorinated multicyclic molecules were successfully obtained in only five or six reaction steps without the need for special handling techniques, as is generally required for thermally unstable organometallic species, representing a reduction of three reaction steps. The improved short-step synthetic protocol was also amenable to the multigram preparation of these promising molecules, which may contribute significantly to the development of novel negative-type LC molecules containing CF2CF2 carbocycles.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

Kumon

Hashishita

Kida

et al. 2018

Beilstein J. Org. Chem.

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“…In a follow‐up publication, Yamada et al describe saturated analogs, that is, symmetrical and unsymmetrical 3,6‐disubstituted 1,1,2,2‐tetrafluorocyclohexanes (e.g. 158 – 160 , Scheme ), from commercially available precursors such as ethyl trifluoroacetate or bromide 73 . As evidenced by single‐crystal X‐ray diffraction, the tetrafluorocyclohexane ring adopts trans ‐configuration.…”

Section: Applications Of Cf2cf2‐containing Compoundsmentioning

confidence: 99%

Advances in the Synthesis and Application of Tetrafluoroethylene‐ and 1,1,2,2‐Tetrafluoroethyl‐Containing Compounds

et al. 2018

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In this review, we provide a comprehensive and critical perspective on the synthesis and application of 1,1,2,2‐tetrafluoroethyl‐ and tetrafluoroethylene‐containing compounds. These structures have been the focus of increasing attention as witnessed by a spectrum of new synthetic approaches, which have recently appeared in the literature. Likewise, applications of molecules containing the CF2CF2 fragment as pharmaceuticals, agrochemicals, pesticides, and advanced materials are described. It is expected that the number of successful applications of these compounds will increase in the future as a result of availability of the synthetic methods outlined here.

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“…2,3-Difluoroaryl motifs such as 3 have proven to be a successful class of negative dielectric anisotropic liquid crystals and the more rigid 1,1,6,7tetrafluoroindane 4 led to an enhanced polarity and improved negative dielectric anisotropy character [8]. Other liquid crystals of this class are the recently reported fluorinated cyclohexane 5 and 1,1,2,2-tetrafluorocyclohexane 6 [9,10], but the complexity of their synthesis has limited their development as practical materials.…”

Section: Introductionmentioning

confidence: 99%

“…Examples of liquid crystal candidates with negative values for dielectric anisotropy (Δε)[6][7][8][9][10].…”

mentioning

confidence: 99%

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

Fang¹,

Al‐Maharik²,

Kirsch³

et al. 2020

Beilstein J. Org. Chem.

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This paper describes the synthesis of a series of organic liquid crystals (LCs) containing selectively fluorinated cyclopropanes at their termini. The syntheses used difluorocarbene additions to olefin precursors, an approach which proved straightforward such that these liquid crystal candidates could be efficiently prepared. Their physical and thermodynamic properties were evaluated and depending on individual structures, they either displayed positive or negative dielectric anisotropy. The study gives some guidance into effective structure–property relationships for the design of LCs containing selectively fluorinated cyclopropane motifs.

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New entry for fluorinated carbocycles: Unprecedented 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane derivatives

Cited by 17 publications

References 65 publications

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

Advances in the Synthesis and Application of Tetrafluoroethylene‐ and 1,1,2,2‐Tetrafluoroethyl‐Containing Compounds

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

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New entry for fluorinated carbocycles: Unprecedented 3,6-disubstituted 1,1,2,2-tetrafluorocyclohexane derivatives

Cited by 17 publications

References 65 publications

Gram-scale preparation of negative-type liquid crystals with a CF2CF2-carbocycle unit via an improved short-step synthetic protocol

Gram-scale preparation of negative-type liquid crystals with a CF2CF2-carbocycle unit via an improved short-step synthetic protocol

Advances in the Synthesis and Application of Tetrafluoroethylene‐ and 1,1,2,2‐Tetrafluoroethyl‐Containing Compounds

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

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Product

Resources

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Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol

Gram-scale preparation of negative-type liquid crystals with a CF₂CF₂-carbocycle unit via an improved short-step synthetic protocol