Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Locke, Gemma M.; Bernhard, Stefan; Senge, Ma­thias O.

doi:10.1002/chem.201804225

Cited by 197 publications

(150 citation statements)

References 564 publications

(841 reference statements)

Supporting

Mentioning

148

Contrasting

Unclassified

Order By: Relevance

“…There is evidence to suggest that the occurrence of N TB phases is a consequence of molecular shape; assuming this to be true, we considered that it should be possible to incorporate isosteric replacements for para substituted benzene rings without detriment to the incidence of these modulated nematic phases. There are a number of saturated hydrocarbons can be considered as isosteric with para substituted benzene, and while 1,4‐disubstituted trans cyclohexane and bicyclo[2.2.2]octane are known within the context of liquid crystalline matter, others ‐ such as 1,4‐disubstituted cubane – remain largely obscure in this field . 1,4‐Cubanes can undergo metal‐catalyzed σ‐bond rearrangement in the presence of silver salts to afford 2,6‐ and 1,3‐ disubstituted cuneanes (pentacyclo[3.3.0.0 2,4 .0 3,7 .0 6,8 ]octanes), with a small number of liquid crystalline derivatives of this wedge‐shaped saturated hydrocarbon being known .…”

Section: Transition Temperatures (T °C) and Associated Enthalpies Omentioning

confidence: 99%

Utilising Saturated Hydrocarbon Isosteres of para Benzene in the Design of Twist‐Bend Nematic Liquid Crystals

Al-Janabi

Mandle

2020

ChemPhysChem

View full text Add to dashboard Cite

The nematic twist-bend (N TB ) liquid crystal phase possesses a local helical structure with a pitch length of a few nanometres and is the first example of spontaneous symmetry breaking in a fluid system. All known examples of the N TB phase occur in materials whose constituent mesogenic units are aromatic hydrocarbons. It is not clear if this is due to synthetic convenience or a bona fide structural requirement for a material to exhibit this phase of matter. In this work we demonstrate that materials consisting largely of saturated hydrocarbons can also give rise to this mesophase.Furthermore, we find that replacement of 1,4-disubstituted benzene with trans 1,4-cyclohexane or 1,4-cubane does not especially alter the transition temperatures of the resulting material nor does it appear to impact upon the heliconical tilt angle. Each of these three units is effectively rigid and linear; calculating the probability distribution of bend angles for each compound reveals that the isosteric groups has little impact on the overall molecular shape, demonstrating the shape-driven nature of the N TB phase. Conversely, we find that incorporation of 2,6-disubstituted cuneane -a saturated hydrocarbon which is rigid but not linear -supresses the formation of the N TB phase.Liquid crystals are a collection of states of matter (mesophases) which possess orientational and/or positional order not found in the liquid state. Different LC mesophase are principally characterised by their degree of positional order; the nematic LC phase possesses long range orientational order, whereas smectic phases also exhibit positional order in one dimension. The discovery of nematic phases in which the average orientational order varies periodically -so called modulated nematics -has recently attracted significant interest. [1][2][3][4][5][6] The twist-bend nematic phase (N TB ) exhibits a heliconical precession of the nematic director through space with a periodic length scale of a few tens of nanometers. [7][8][9] This phase is typically found in materials comprising two or more mesogenic units which are mutually appended by a central spacer of such a length as to impart a gross bent shape. The incidence of the N TB phase is intimately linked to molecular shape, specifically the bend angle between adjacent mesogenic units. [10][11][12][13][14] The mesogenic units themselves are almost exclusively constructed from multiple benzene rings, and to date (as far as the authors are aware) the spacer is always appended to an aromatic ring rather than a saturated hydrocarbon; [15][16][17][18][19][20][21][22][23] it is not clear if this is a consequence of synthetic convenience or a real structural requirement for materials to exhibit this phase of matter.

show abstract

Section: Transition Temperatures (T °C) and Associated Enthalpies Omentioning

confidence: 99%

Utilising Saturated Hydrocarbon Isosteres of para Benzene in the Design of Twist‐Bend Nematic Liquid Crystals

Al-Janabi

Mandle

2020

ChemPhysChem

View full text Add to dashboard Cite

show abstract

“…solubility, compared to aryl systems. [6][7][8] Although propellanes with larger ring sizes, such as the intriguing [3.3.3]propellanes do not share the same properties of their counterparts with smaller rings, [9][10][11] they have equally fascinated many organic chemists by the originality of their structures and by the challenge that their syntheses represent.…”

Section: Introductionmentioning

confidence: 99%

Occurrence, synthesis and applications of natural and designed [3.3.3]propellanes

et al. 2020

View full text Add to dashboard Cite

show abstract

“…The recent focus on saturated hydrocarbons as structural motifs ('escape from flatland') [1] has drawn the attention of many groups towards bicyclo[1.1.1]pentanes (BCPs). [2] Derived from [1.1.1]propellane (4), there have been numerous contributions to the synthesis of BCPs with CÀ C, [3] CÀ N [4] and CÀ S [5] bond formations. The modification of these products is an emerging field [6] and besides oxidation [5a,7] BCP sulfides 5 have not been addressed so far.…”

Section: Introductionmentioning

confidence: 99%

Bicyclo[1.1.1]pentyl Sulfoximines: Synthesis and Functionalizations

et al. 2020

View full text Add to dashboard Cite

Herein we present the first synthesis of bicyclo[1.1.1]pentyl (BCP) sulfoximines from the corresponding sulfides. Both BCPs and sulfoximines are bioisosteres used in medicinal chemistry and therefore desirable motifs. The access to BCP sulfides was enabled by the thiol addition to [1.1.1]propellane as published before. A broad scope with specific limitations was discovered for the sulfoximination. To diversify the sulfoximines, N‐acylations and N‐arylations were performed. As the N‐arylation was low yielding we optimized the copper(I) catalyzed reaction. A wide range of aryl iodides could be deployed and competitive reactions showed that aryl bromides react equally fast. In a scale‐up we prepared a suitable precursor for a BCP drug analogue. In this work several molecular structures could be determined by single‐crystal X‐ray diffraction.

show abstract

Nonconjugated Hydrocarbons as Rigid‐Linear Motifs: Isosteres for Material Sciences and Bioorganic and Medicinal Chemistry

Cited by 197 publications

References 564 publications

Utilising Saturated Hydrocarbon Isosteres of para Benzene in the Design of Twist‐Bend Nematic Liquid Crystals

Utilising Saturated Hydrocarbon Isosteres of para Benzene in the Design of Twist‐Bend Nematic Liquid Crystals

Occurrence, synthesis and applications of natural and designed [3.3.3]propellanes

Bicyclo[1.1.1]pentyl Sulfoximines: Synthesis and Functionalizations

Contact Info

Product

Resources

About