Control of a Chiral Property of a Calix[3]aramide: The Racemization Suppressed by Intramolecular Cyclic Hydrogen Bonds and DMSO–H<sub>2</sub>O System-Induced Spontaneous Resolution

Katagiri, Kosuke; Komagawa, Shinsuke; Uchiyama, Masanobu; Yamaguchi, Kentaro; Azumaya, Isao

doi:10.1021/acs.orglett.5b01455

Cited by 7 publications

(3 citation statements)

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“…Amino-dithienophospholes ( 6a ) are also robust precursors for the generation of a series of phosphinamides ( 7a–e ) with unique hydrogen-bond self-organization properties (Scheme ). Notably, the central PO–NH fragments in 7 give rise to a much richer set of secondary bonding and structures when compared to the CO–NH-based carbamide congeners. , While the latter are strictly limited to two bonding motifs, syn /head-to-head (i.e., 0°) and anti/ head-to-tail (i.e., 180°), the P-based system essentially provides a highly adjustable dial that easily adapts to any given secondary/tertiary structure dictated by other intermolecular interaction types . To this end, the combination of intermolecular π–π interactions and H-bonding in 7a causes the molecules to π-stack in an unusual H-aggregate-type 1D columnar arrangement (Figure a), with head-to-tail linked PO–NH units at an angle of 131° between the PO and NH groups.…”

Section: Enhancing σ*−π* Interactions Through P–p Bond Formationmentioning

confidence: 99%

“…23,24 While the latter are strictly limited to two bonding motifs, syn/ head-to-head (i.e., 0°) and anti/head-to-tail (i.e., 180°), the Pbased system essentially provides a highly adjustable dial that easily adapts to any given secondary/tertiary structure dictated by other intermolecular interaction types. 25 To this end, the combination of intermolecular π−π interactions and Hbonding in 7a causes the molecules to π-stack in an unusual H-aggregate-type 1D columnar arrangement (Figure 5a), with head-to-tail linked PO−NH units at an angle of 131°between the PO and NH groups. By contrast, the π-conjugated backbones in 7c align in a syn-type, parallel fashion favoring a zigzag pathway for H-bonding with PO−NH at an intermediate angle of 47°between the PO and NH groups.…”

Section: Enhancing σ*−π* Interactions Through P−p Bond Formationmentioning

confidence: 99%

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Unique Phosphorus-Based Avenues for the Tuning of Functional Materials

2023

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Metrics & MoreArticle Recommendations CONSPECTUS: Recent ground-breaking advances in synthetic chemistry have transformed main-group molecules from simple laboratory curiosities into powerful materials for a range of applications in all realms of life. Electron-accepting or -deficient materials, in particular, have been the focus of development since their generally limited availability and stability have been major hurdles in establishing new practical applications. In addition to the general requirements for the design of these materials, a deeper understanding of their inherent electronics and molecular interactions is a requirement for the successful expansion of their utility. Previously, the incorporation of electron-deficient main-group elements, such as boron, into a conjugated organic framework was considered to be an effective route toward the synthesis of high-performing electron-accepting materials. However, challenging conditions such as the need for bulky substituents for kinetic stabilization, air-free and moisture-sensitive synthesis, and restricted storage abilities have led to the investigation of other elements across the periodic table to be used in a similar vein. Lately, heavier main-group elements such as Si, Ge, P, As, Sb, Bi, S, Se, and Te have also proven to be advantageous for electron-accepting materials as they exhibit polarizable molecular orbitals that are easily accessible to electrons or nucleophiles. This has laid the foundation for materials chemistry research on a variety of applications, including optoelectronic devices such as OLEDs, organic photovoltaics, energy storage such as in batteries and capacitors, fluorescent sensors with both biological and physiological applications, organocatalysis and synthesis, and many more. Among the main-group-element-based materials, organophosphorus species are privileged as their frontier orbitals are easily altered by chemical modification or/and structural and geometrical manipulations at the phosphorus center itself, without the need for kinetic stabilization, or through electronic modification of the conjugated system. The five-membered phosphorus-based heterocycle, phosphole, is a particularly interesting motif in this context, and extensive studies on the corresponding materials have uncovered the rich fundamentals of the σ*−π* interaction that imparts intriguing accepting properties while sustaining morphological and physiological stability for utilization in real-life scenarios. Moreover, beyond the σ*−π* interaction in phospholes that is key to many of their acceptor properties as a material, the use of phosphorus also gives rise to easily accessible, low-lying antibonding orbitals. They pave the way for Lewis acid phosphorus species that, despite being considered to be electron-rich species in general, open up several possibilities for intriguing chemical reactivity through hypervalency. Herein, we representatively discuss some recent advancements through the various approaches that leverage the unique structures and electronics...

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Section: Enhancing σ*−π* Interactions Through P–p Bond Formationmentioning

confidence: 99%

Section: Enhancing σ*−π* Interactions Through P−p Bond Formationmentioning

confidence: 99%

Unique Phosphorus-Based Avenues for the Tuning of Functional Materials

2023

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“…Because the carbon cation is a typical soft acid, the S-terminus rather than the N-terminus of thiourea will serve as a nucleophile site to react with the carbon to afford the cyclizing product 3 . For the aza-Michael addition, DMSO, as broadly applied, will easily form hydrogen bonds − with the hydrogens from the amino group of thiourea to activate the N–H bond. An N-terminal nucleophile active site is then produced from the weak N–H bond of 6 , which will attack the carbon and give the cyclized product 4 .…”

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confidence: 99%

Catalyst-Free Chemoselective Synthesis of 3,4-Dihydroquinazoline-2-thiones and 2-Imino[1,3]benzothiazines

et al. 2016

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A solvent-controlled catalyst-free chemoselective reaction was developed. Both 3,4-dihydroquinazoline-2-thiones and 2-imino[1,3]benzothiazines could be efficiently constructed by the reaction of 2-amino chalcones with isothiocyanates via two different chemoselective reactions depending on the solvents. The reaction was modulated by the solvents to proceed via either aza-Michael addition or thia-Michael addition as the major reaction with excellent yields.

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Dithienophosphole‐Based Phosphinamides with Intriguing Self‐Assembly Behavior

2016

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A new, highly adaptable type of phosphinamide‐based hydrogen bonding is representatively demonstrated in π‐conjugated phosphole materials. The rotational flexibility of these intermolecular P=O−H−N hydrogen bonds is demonstrated by X‐ray crystallography and variable‐concentration NMR spectroscopy. In addition to crystalline compounds, phosphinamide hydrogen bonding was successfully introduced into the self‐assembly of soft crystals, liquid crystals, and organogels, thus highlighting the high general value of this type of interaction for the formation of organic soft materials.

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Control of a Chiral Property of a Calix[3]aramide: The Racemization Suppressed by Intramolecular Cyclic Hydrogen Bonds and DMSO–H₂O System-Induced Spontaneous Resolution

Cited by 7 publications

References 38 publications

Unique Phosphorus-Based Avenues for the Tuning of Functional Materials

Unique Phosphorus-Based Avenues for the Tuning of Functional Materials

Catalyst-Free Chemoselective Synthesis of 3,4-Dihydroquinazoline-2-thiones and 2-Imino[1,3]benzothiazines

Dithienophosphole‐Based Phosphinamides with Intriguing Self‐Assembly Behavior

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Control of a Chiral Property of a Calix[3]aramide: The Racemization Suppressed by Intramolecular Cyclic Hydrogen Bonds and DMSO–H2O System-Induced Spontaneous Resolution

Cited by 7 publications

References 38 publications

Unique Phosphorus-Based Avenues for the Tuning of Functional Materials

Unique Phosphorus-Based Avenues for the Tuning of Functional Materials

Catalyst-Free Chemoselective Synthesis of 3,4-Dihydroquinazoline-2-thiones and 2-Imino[1,3]benzothiazines

Dithienophosphole‐Based Phosphinamides with Intriguing Self‐Assembly Behavior

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Resources

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Control of a Chiral Property of a Calix[3]aramide: The Racemization Suppressed by Intramolecular Cyclic Hydrogen Bonds and DMSO–H₂O System-Induced Spontaneous Resolution