Synthèses Asymétriques Potentielles Impliquant la Réaction “Ene”

Hassine, Béchir Ben; Gorsane, Mohamed; Pecher, Jacques; Martin, R. H.

doi:10.1002/bscb.19870961013

Cited by 20 publications

(39 citation statements)

References 17 publications

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“…In 1976, a low enantioselectivity in the reduction of a racemic [6]helicene derivative with potassium metal was observed by circular dichroism spectroscopy in the optically active solvent (+)-2,3-dimethoxybutane. Hexahelicene radical anion was enantioselectively formed.…”

Section: Helicene Deracemizationmentioning

confidence: 99%

“…Another efficient asymmetric reaction (Scheme 2) came from a highly diastereoselective ene reaction with cyclohexene at 0 1C, in the presence of the catalyst SnCl 4 , with the E-crotonate ester of (rac)-2-hydroxy- [7]helicene (86% yield; 100% d.e.). 6 Usually, a metallic center plays a pivotal role in asymmetric catalysis while binding together two reactive species (or substrates) in a chiral environment generated by a ligand. The last reaction does not involve an apparent precomplexation of cyclohexene in a metal complex.…”

Section: Helicenes In Diastereoselective Stoichiometric Reactionsmentioning

confidence: 99%

“…Additionally, reactions at higher temperatures might be possible without racemizing the helicene ligand (i.e. [6]helicenes or higher helicenes). It would be an advantage compared to a lower-energy thermal racemization of many binaphthyl ligands.…”

Section: Helicenes As Chiral Ligands or As Additives In Asymmetric Ca...mentioning

confidence: 99%

“…Of a high interest, a few mol% (as low as 0.13 mol%) of non-functionalized enantioenriched or enantiopure [5]-or [6]helicene could be sufficient as chiral inducers in the enantioselective addition of diisopropyl zinc to a functionalized pyrimidine aldehyde (88-95%; 56-95% e.e.). 11 Apparently, the first catalysis by a chiral hydrocarbon, such as a helicene, might be explained by the formation of diastereomeric charge-transfer complexes with the aromatic aldehyde in solution and/or in the formation of higher aggregates (Scheme 4).…”

Section: Helicenes As Chiral Ligands or As Additives In Asymmetric Ca...mentioning

confidence: 99%

“…The resolution relied on the separation of diastereomeric Pd-complexes. 17 A mixed ligand was also synthesized, incorporating a methoxy function and a diphenylphosphino group at the periphery of a [6]helicene (Fig. 1).…”

Section: Helicenes As Chiral Ligands or As Additives In Asymmetric Ca...mentioning

confidence: 99%

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One hundred years of helicene chemistry. Part 3: applications and properties of carbohelicenes

2013

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Carbohelicenes are a class of fascinating chiral helical molecules which have a rich history in chemistry. Over a period of almost 100 years, chemists have developed many methods to prepare them in a racemic or in a non-racemic form. They also possess a series of interesting chiral, physical, electronic and optical properties. However, their utilization in chemistry or chemistry-related fields has rarely appeared in a detailed and comprehensive review. It is the purpose of this review to collect fundamental applications and functions involving carbohelicenes in various disciplines such as in materials science, in nanoscience, in biological chemistry and in supramolecular chemistry. From the numerous synthetic methodologies reported up to now, carbohelicenes and their derivatives can be tailor-made for a better involvement in several subfields. Among those domains are: nanosciences, chemosensing, liquid crystals, molecular switches, polymers, foldamers, supramolecular materials, molecular recognition, conductive and opto-electronic materials, nonlinear optics, chirality studies and asymmetric synthesis. Helicene chemistry is now at a developmental stage, where sufficient application data are now collected and are extremely useful. They provide many more ideas for setting up the basis for future innovative applications.

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Section: Helicene Deracemizationmentioning

confidence: 99%

Section: Helicenes In Diastereoselective Stoichiometric Reactionsmentioning

confidence: 99%

Section: Helicenes As Chiral Ligands or As Additives In Asymmetric Ca...mentioning

confidence: 99%

Section: Helicenes As Chiral Ligands or As Additives In Asymmetric Ca...mentioning

confidence: 99%

Section: Helicenes As Chiral Ligands or As Additives In Asymmetric Ca...mentioning

confidence: 99%

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One hundred years of helicene chemistry. Part 3: applications and properties of carbohelicenes

2013

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Strained Aromatic Molecules

Smith

Liebman

Hopf

et al. 2009

Strained Hydrocarbons

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B,N‐Embedded Hetero[9]helicene Toward Highly Efficient Circularly Polarized Electroluminescence

Guo,

Zhao,

Tan

et al. 2024

Angewandte Chemie

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The intrinsic helical p‐conjugated skeleton makes helicenes highly promising for circularly polarized electroluminescence (CPEL). Generally, carbon helicenes undergo low external quantum efficiency (EQE), while the incorporation of multi‐resonance thermally activated delayed fluorescence (MR‐TADF) BN structure has achieved an improvement. However, the reported B,N‐embedded helicenes all show low electroluminescence dissymmetry factors (gEL) typically hovering around 1 × 10‐3. Therefore, the development of B,N‐embedded helicenes with both high EQE and gEL value is crucial for achieving highly efficiency CPEL. Herein, a facile approach to synthesize B,N‐embedded hetero[9]helicenes, BN[9]H, is presented. BN[9]H shows a bright photoluminescence peaking at 578 nm with high luminescence dissymmetry factor (|glum|) up to 5.8 × 10‐3, attributed to its inherited MR‐TADF property and intrinsic helical skeleton. Furthermore, circularly polarized OLED devices incorporating BN[9]H as emitter show maximum EQE of 35.5%, a small full width at half‐maximum of 48 nm, and more importantly, a high |gEL| of 6.2 × 10‐3. The Q‐factor (|EQE × gEL|) of CP‐OLEDs is determined to be 2.2 × 10‐3, which is the highest among helicene analogues. This work provides a new approach for the synthesis of higher helicenes and paves a new way for the construction of highly efficient CPEL materials.

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Synthèses Asymétriques Potentielles Impliquant la Réaction “Ene”

Abstract: Dedie a la memoire de Nicole Defay, Dr. Sc.

Cited by 20 publications

References 17 publications

One hundred years of helicene chemistry. Part 3: applications and properties of carbohelicenes

One hundred years of helicene chemistry. Part 3: applications and properties of carbohelicenes

Strained Aromatic Molecules

B,N‐Embedded Hetero[9]helicene Toward Highly Efficient Circularly Polarized Electroluminescence

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