Multiplicative enhancement of stereoenrichment by a single catalyst for deracemization of alcohols

Science, Journal Year: 2023, Volume and Issue: 382(6669), P. 458 - 464

Published: Oct. 26, 2023

Stereochemical enrichment of a racemic mixture by deracemization must overcome unfavorable entropic effects as well the principle microscopic reversibility; recently, photochemical reaction pathways unveiled energetic input light have led to innovations toward this end, most often ablation stereogenic C(sp3)-H bond. We report photochemically driven protocol in which single chiral catalyst two mechanistically different steps, C-C bond cleavage and formation, achieve multiplicative enhancement stereoinduction, leads high levels stereoselectivity. Ligand-to-metal charge transfer excitation titanium coordinated phosphoric acid or bisoxazoline efficiently enriches alcohols that feature adjacent fully substituted centers enantiomeric ratios up 99:1. Mechanistic investigations support pathway sequential radical-mediated scission formation through common prochiral intermediate reveal that, although overall stereoenrichment is high, selectivity each individual step moderate.

Language: Английский

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Catalytic Deracemization Reactions

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(20), P. 10917 - 10929

Published: May 13, 2023

Deracemization, which converts a racemate into its single enantiomer without separation of the intermediate, has gained renewed interest in asymmetric synthesis with inherent atomic economy and high efficiency. However, this ideal process requires selective energy input delicate reaction design to surmount thermodynamical kinetical constraints. With rapid development catalysis, many catalytic strategies concert exogenous have been exploited facilitate nonspontaneous enantioenrichment. In perspective, we will discuss basic ideas accomplish deracemization, categorized by three major sources including chemical (redox)-, photo- mechanical from attrition. Emphasis be given features underlying deracemization mechanism together perspectives on future development.

Language: Английский

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Catalytic Photochemical Deracemization via Short‐Lived Intermediates

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(50)

Published: July 10, 2023

Upon irradiation in the presence of a suitable chiral catalyst, racemic compound mixtures can be converted into enantiomerically pure compounds with same constitution. The process is called photochemical deracemization and involves formation short-lived intermediates. By opening different reaction channels for forward to intermediate re-constitution molecule, entropically disfavored becomes feasible. Since discovery first 2018, field has been growing rapidly. This review comprehensively covers research performed area discusses current developments. It subdivided according mode action respective substrate classes. focus this on scope individual reactions discussion mechanistic details underlying presented reaction.

Language: Английский

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Redox-powered autonomous unidirectional rotation about a C–C bond under enzymatic control

Published: Feb. 16, 2024

Living biological systems rely on the continuous operation of chemical reaction networks. These networks sustain out-of-equilibrium regimes in which energy is continually converted into controlled mechanical work and motion. Out-of-equilibrium have also enabled design successful development artificial autonomously operating molecular machines, comprising pairs formally—but non-microscopically—reverse pathways drive motion at level. In systems, concurrent multiple by chemoselectivity enzymes their co-factors, nature’s dissipative involve several classes reactions. contrast, reactivity that has been harnessed to develop pursuit machines limited a single type. Only small number synthetic exhibit chemically fuelled molecular-level motion, all exploit same class acylation–hydrolysis reaction. Here we show redox network, oxidation reduction pathways, can autonomous unidirectional about C–C bond most structurally simple motor yet reported, an achiral biphenyl. The combined use oxidant reductant as fuels, directionality motor, are both exploiting enantioselectivity functional separation inherent enzyme catalysis.

Language: Английский

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Enzymatic and Chemo–catalytic Redox Deracemization: Recent Progress

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(14)

Published: Feb. 5, 2024

Abstract The precise synthesis of chiral small molecules is a core research area in chemical science. Deracemization, an appealing technology that converts racemate to its single enantiomer with the same constitution theoretical 100 % yield, appears as straightforward and efficient strategy asymmetric synthesis. A cascading redox sequence was most employed approach drive deracemization through destroy recreate stereocenter given molecule. This review mainly focuses on progress driven by respective biocatalysis chemo–catalysis. In particular, each section will be subdivided according action modes, substrate classes perspectives future development.

Language: Английский

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Visible Light-Induced, Nickel-Catalyzed Late-Stage 4-Alkylation of Hantzsch Esters with Alkyl Bromide

The Journal of Organic Chemistry, Journal Year: 2024, Volume and Issue: 89(15), P. 10987 - 10997

Published: July 22, 2024

Herein, visible light-induced, nickel-catalyzed direct functionalization of the Hantzsch esters (HEs) with readily accessible alkyl bromides has been successfully achieved by taking advantage HE as reductant and substrate through an aromatization-dearomatization process. In this strategy, single electron reduction reactive Ni(I) species is essential for success late-stage transformation. A wide range 4-alkyl-1,4-dihydropyridines were rapidly assembled in moderate to good yields under mild conditions, rendering photoinduced approach attractive synthetic medicinal chemistry.

Language: Английский

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Mn(III) Catalyzed Cascade Cross-coupling / Annulation / C(O)-C Bond Insertion / Rearrangement: Access to Multi-substituted Indolenines in Water

Green Synthesis and Catalysis, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Language: Английский

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Enantioselective Synthesis of 2-Aryl-3,3-Disubstituted Indolines from 3H-Indoles via Deracemization

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: April 8, 2025

An enantioselective synthesis of 2-aryl 3,3-disubstituted 3H-indoles has been successfully developed via a deracemization process involving borane-catalyzed hydrogenation and chiral phosphoric-acid-catalyzed asymmetric transfer hydrogenation. A variety were effective substrates to afford the desired indolines in 86-95% yields with 45-92% ee's.

Language: Английский

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Asymmetric Chiral Photocatalysts

ACS Catalysis, Journal Year: 2025, Volume and Issue: unknown, P. 7543 - 7577

Published: April 22, 2025

Language: Английский

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Advancements in organocatalysis for radical-mediated asymmetric synthesis: A recent perspective

Chem Catalysis, Journal Year: 2023, Volume and Issue: 4(4), P. 100812 - 100812

Published: Nov. 20, 2023

Language: Английский

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