Chiral Photocatalyst Structures in Asymmetric Photochemical Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 1654 - 1716

Опубликована: Окт. 4, 2021

Asymmetric catalysis is a major theme of research in contemporary synthetic organic chemistry. The discovery general strategies for highly enantioselective photochemical reactions, however, has been relatively recent development, and the variety photoreactions that can be conducted stereocontrolled manner consequently somewhat limited. photocatalysis complicated by short lifetimes high reactivities characteristic photogenerated reactive intermediates; design catalyst architectures provide effective enantiodifferentiating environments these intermediates while minimizing participation uncontrolled racemic background processes proven to key challenge progress this field. This review provides summary chiral structures have studied solution-phase asymmetric photochemistry, including sensitizers, inorganic chromophores, soluble macromolecules. While some photocatalysts are derived from privileged both ground-state transformations, others structural designs unique offer insight into logic required photocatalysis.

Язык: Английский

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Green Organo-Photooxidative Method for the Degradation of Methylene Blue Dye

ACS Omega, Год журнала: 2024, Номер 9(10), С. 12069 - 12083

Опубликована: Фев. 28, 2024

This study used an organophoto-oxidative material to degrade the toxic azo dye, methylene blue (MB), due its hazardous effects on aquatic life and humans. MB is traditionally degraded using metal-based catalysts, resulting in high costs. Several organic acids were screened for organo-photooxidative applications against various dyes, ascorbic acid (AA), also known as vitamin C, was found be best degradation photooxidative activity. It eco-friendly, edible, efficient material. A photocatalytic box has been developed of that when AA added, efficiency increased from 42 95% within 240 min. Different characterization techniques, such HPLC GC-MS, after structural elucidation products. DFT done investigation mechanistic behind process. statistical tool, RSM, optimization parameters (concentration catalyst, time). develops sustainable effective solutions wastewater treatment.

Язык: Английский

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Enantioselective [2 + 2] Photocycloaddition via Iminium Ions: Catalysis by a Sensitizing Chiral Brønsted Acid

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(25), С. 9350 - 9354

Опубликована: Июнь 22, 2021

N,O-Acetals derived from α,β-unsaturated β-aryl substituted aldehydes and (1-aminocyclohexyl)methanol were found to undergo a catalytic enantioselective [2 + 2] photocycloaddition variety of olefins (19 examples, 54–96% yield, 84–98% ee). The reaction was performed by visible light irradiation (λ = 459 nm). A chiral phosphoric acid (10 mol %) with an (R)-1,1′-bi-2-naphthol (binol) backbone served as the catalyst. displays two thioxanthone groups attached position 3 3′ binol core via meta-substituted phenyl linker. NMR studies confirmed formation iminium ion which is counterion in hydrogen-bond assisted pair. activity rests on presence moieties enable facile triplet energy transfer efficient enantioface differentiation.

Язык: Английский

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An update on chiral phosphoric acid organocatalyzed stereoselective reactions

Organic & Biomolecular Chemistry, Год журнала: 2023, Номер 21(17), С. 3477 - 3502

Опубликована: Янв. 1, 2023

This review article presents an in-depth analysis of the strategies and methodologies for using chiral phosphoric acids as organocatalysts in asymmetric syntheses from recent literature.

Язык: Английский

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TBADT‐Mediated Photocatalytic Stereoselective Radical Alkylation of Chiral N‐Sulfinyl Imines: Towards Efficient Synthesis of Diverse Chiral Amines

Chemistry - A European Journal, Год журнала: 2024, Номер 30(24)

Опубликована: Фев. 20, 2024

Abstract Herein we describe a sustainable and efficient photocatalytic method for the stereoselective radical alkylation of chiral sulfinyl imines. By employing readily available non‐prefunctionalized precursors cost‐effective TBADT as direct HAT photocatalyst, successfully obtain diverse amines with high yields excellent diastereoselectivity under mild conditions. This provides an approach accessing array medicinally relevant compounds, including both natural synthetic α‐amino acids, aryl ethyl amines, other structural motifs commonly found in approved pharmaceuticals product.

Язык: Английский

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Controlling Stereoselectivity with Noncovalent Interactions in Chiral Phosphoric Acid Organocatalysis

Chemical Reviews, Год журнала: 2025, Номер unknown

Опубликована: Март 18, 2025

Chiral phosphoric acids (CPAs) have emerged as highly effective Brønsted acid catalysts in an expanding range of asymmetric transformations, often through novel multifunctional substrate activation modes. Versatile and broadly appealing, these benefit from modular tunable structures, compatibility with additives. Given the unique types noncovalent interactions (NCIs) that can be established between CPAs various reactants─such hydrogen bonding, aromatic interactions, van der Waals forces─it is unsurprising catalyst systems become a promising approach for accessing diverse chiral product outcomes. This review aims to provide in-depth exploration mechanisms by which impart stereoselectivity, positioning NCIs central feature connects broad spectrum catalytic reactions. Spanning literature 2004 2024, it covers nucleophilic additions, radical atroposelective bond formations, highlighting applicability CPA organocatalysis. Special emphasis placed on structural mechanistic features govern CPA-substrate well tools techniques developed enhance our understanding their behavior. In addition emphasizing details stereocontrolling elements individual reactions, we carefully structured this natural progression specifics broader, class-level perspective. Overall, findings underscore critical role catalysis significant contributions advancing synthesis.

Язык: Английский

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Strategies toward the Difunctionalizations of Enamide Derivatives for Synthesizing α,β-Substituted Amines

Accounts of Chemical Research, Год журнала: 2022, Номер 55(22), С. 3265 - 3283

Опубликована: Ноя. 1, 2022

ConspectusEnamide and enecarbamate derivatives containing a nucleophilic center at the β-position from their nitrogen atom as well latent electrophilic site α-position are interesting motifs in organic chemistry. This dual reactivity─analogous that of enamines─enables difunctionalization increased structural complexity. Furthermore, an electron-withdrawing group on drastically increases stability. In respect, enamides enecarbamates excellent partners for multicomponent transformations, our research primarily focuses these compounds particular.Difunctionalization generally occurs through addition electrophile to form iminium, which can subsequently react with species. Although potent, such approach is highly challenging due low stability intermediate leading undesired hydrolysis or oligomerization. Epimerization, competitivity, compatibility issues between reaction additional hindrances developing methodologies. To overcome limitations, we described many complementary strategies.To control enantioselectivity chiral phosphoric acids were found be particularly well-suited activate multiple reactants formation hydrogen bonds network, allowing organized transition state pocket. Interestingly, when deprotonated phosphates, they also play role ligands Lewis acidic metals.To avoid iminium oligomerization, successfully used stabilized α-arylated enamides. However, this was restricted simple β-position. achieve difunctionalizations α-unsubstituted derivatives, explored reversibly linked nucleophile address problem. Alternatively, devised sequential methodology resolving issue N-acyl based its trapping using temporary (alcohol thiol). agent could further displaced by desired final α-substituent under photocatalytic activation. led us design new bifunctional acid catalysts bearing chromophores merge asymmetric organocatalysis photochemistry.These photocatalysis studies incited focus radical processes manage original functionalizations would not feasible otherwise. β-Alkylation β-trifluoromethylation via visible-light-promoted transfer additions performed. As β-allylations remained unattainable precedent methods, eventually turned attention cerium(IV)-mediated oxidative single electron transfers. It allowed singly occupied molecular orbital activation substrates elicit umpolung reactivity.Thus, functionalization appears valid synthetic strategy obtaining important building blocks agrochemical, pharmaceutical, cosmetic industries, including diamines, haloamines, aminotryptamines, less accessible trifluoromethylated allylic compounds.

Язык: Английский

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Bifunctional organic photocatalysts for enantioselective visible-light-mediated photocatalysis

Nature Synthesis, Год журнала: 2023, Номер 2(10), С. 913 - 925

Опубликована: Окт. 2, 2023

Язык: Английский

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Hybrid Catalysts for Enantioselective Photo-Phosphoric Acid Catalysis

The Journal of Organic Chemistry, Год журнала: 2023, Номер 88(10), С. 6509 - 6522

Опубликована: Апрель 26, 2023

The syntheses of two novel, organic, and chiral photocatalysts are presented. By combining donor–acceptor cyanoarene-based with a phosphoric acid, bifunctional catalysts have been designed. In preliminary proof-of-concept reactions, their use in both enantioselective energy transfer photoredox catalysis is demonstrated.

Язык: Английский

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Catalytic asymmetric synthesis of 1,2-diamines

Chemical Society Reviews, Год журнала: 2024, Номер 53(15), С. 7983 - 8085

Опубликована: Янв. 1, 2024

The asymmetric catalytic synthesis of 1,2-diamines has received considerable interest, due to their presence in biologically active compounds and applications for the development synthetic building blocks, chiral ligands organocatalysts.

Язык: Английский

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