Catalytic Enantioselective Addition of Prochiral Radicals to Vinylpyridines

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(13), P. 5437 - 5443

Published: March 13, 2019

Pyridine, one of the most important azaarenes, is ubiquitous in functional molecules. The electronic properties pyridine have been exploited to trigger asymmetric transformations prochiral species as a direct approach for accessing chiral derivatives. However, full potential this synthetic strategy construction enantioenriched γ-functionalized pyridines remains untapped. Here, we describe first enantioselective addition radicals vinylpyridines under cooperative photoredox and catalysis mediated by visible light. reductive couplings with aldehydes, ketones, imines were achieved employing Brønsted acid activate reaction partners provide stereocontrol via H-bonding interactions. Valuable γ-secondary/tertiary hydroxyl- amino-substituted obtained high yields good excellent enantioselectivities.

Language: Английский

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Catalytic Reductive Cross Coupling and Enantioselective Protonation of Olefins to Construct Remote Stereocenters for Azaarenes

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(10), P. 4024 - 4031

Published: March 2, 2021

A novel enantioselective protonation protocol that is triggered by reductive cross coupling of olefins reported. When under cooperative photoredox and chiral hydrogen-bonding catalytic conditions using a terminal reductant, various α-branched vinylketones with diverse vinylazaarenes could provide important enantioenriched azaarene derivatives containing tertiary stereocenters at their remote δ-position high yields enantioselectivities. This reaction system also suitable for vinylazaarenes, thus successfully assembling elusive 1,4-stereocenters. The convenient late-stage modifications products, especially the formation ε-tertiary ε-heteroquaternary carbon stereocenters, further highlight synthetic value this method. Control experiments density functional theory (DFT) calculations were conducted to elucidate plausible mechanism origins regioselectivity stereoselectivity.

Language: Английский

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Cooperative photoredox and chiral hydrogen-bonding catalysis

Organic Chemistry Frontiers, Journal Year: 2020, Volume and Issue: 7(10), P. 1283 - 1296

Published: Jan. 1, 2020

Chiral hydrogen-bonding catalysis is a classic strategy in asymmetric organocatalysis. Recently, it has been used to cooperate with photoredox catalysis, becoming powerful tool access optical pure compounds via radical-based transformations.

Language: Английский

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Catalytic Asymmetric Hydrophosphinylation of 2‐Vinylazaarenes to Access P‐Chiral 2‐Azaaryl‐Ethylphosphine Oxides

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(16)

Published: Feb. 22, 2023

A chiral Brønsted acid-catalysed asymmetric hydrophosphinylation of 2-vinylazaarenes by secondary phosphine oxides is described. variety P-chiral 2-azaaryl-ethylphosphine are synthesized with high yields and ees, which both the substituents phosphines azaarenes can be flexibly modulated, underscoring an exceptionally broad scope substrates. These adducts valuable to metal catalysis since resultant tertiary from reduction them verified as a kind effective C1 -symmetric 1,5-hybrid P,N-ligands. Importantly, this platform enables generic efficient kinetic resolution oxides. It thus provides expedient approach access enantiomers derived hydrophosphinylation, further improving utility method.

Language: Английский

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Photoredox-Catalyzed Enantioselective α-Deuteration of Azaarenes with D2O

iScience, Journal Year: 2019, Volume and Issue: 16, P. 410 - 419

Published: June 1, 2019

The site-specific incorporation of deuterium (D) into small molecules is frequently used to access isotopically labeled compounds with broad utility in many research areas, such as drug development, mechanistic studies, and NMR analyses. Nevertheless, the deuteration a stereocenter an enantioselective manner, which could slow metabolism improve bioavailability bioactive molecules, remains challenging owing lack established catalytic methods. Here, we report asymmetric α-deuteration strategy for azaarenes inexpensive D2O source. A cooperative visible light-driven photoredox chiral Brønsted acid-catalyzed system using Hantzsch ester terminal reductant has been developed, enables racemic α-chloro-azaarenes prochiral azaarene-substituted ketones experience single-electron reduction-enantioselective process. transition metal-free method provides important α-deuterated satisfactory yields good excellent enantioselectivities (up 99% ee) substantial incorporation.

Language: Английский

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Enantioselective reduction of azaarene-based ketones via visible light-driven photoredox asymmetric catalysis

Chemical Communications, Journal Year: 2019, Volume and Issue: 55(52), P. 7534 - 7537

Published: Jan. 1, 2019

An enantioselective reduction of azaarene-based ketones through photoredox asymmetric catalysis is reported. With a transition metal-free dual catalytic system including chiral phosphoric acid and photosensitizer DPZ mediated by visible light, the transformations involved tandem process involving double single-electron-transfer reductions protonation, providing valuable alcohols in high yields (up to >99%) with good excellent enantioselectivities 97% ee).

Language: Английский

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NiH-Catalyzed Regio- and Enantioselective Hydroalkylation for the Synthesis of β- or γ-Branched Chiral Aromatic N-Heterocycles

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(40), P. 22122 - 22134

Published: Sept. 25, 2023

A nickel hydride-catalyzed regio- and enantioselective hydroalkylation reaction was developed to give access a library of chiral β- or γ-branched aromatic N-heterocycles. This intriguing asymmetric transformation features excellent selectivities, step- atom-economies, generating two kinds products through one synthetic strategy. Furthermore, the possible mechanism extensively investigated using numerous control experiments density functional theory calculations.

Language: Английский

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Applications of Hantzsch Esters in Organocatalytic Enantioselective Synthesis

Catalysts, Journal Year: 2023, Volume and Issue: 13(2), P. 419 - 419

Published: Feb. 16, 2023

Hantzsch esters (1,4-dihydropyridine dicarboxylates) have become, in this century, very versatile reagents for enantioselective organic transformations. They can act as hydride transfer agents to reduce, regioselectively, a variety of multiple bonds, e.g., C=C and C=N, under mild reaction conditions. are excellent the dearomatization heteroaromatic substances, participate readily cascade processes. In last few years, they also become useful photoredox reactions. sacrificial electron hydrogen donors when 4-alkyl or 4-acyl-substituted, alkyl acyl radical agents. These reactions may take place presence absence photocatalyst. This review surveys literature published area five years.

Language: Английский

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Copper(I)‐Catalyzed Conjugate Addition/Enantioselective Protonation with Selenols and α‐Substituted α,β‐Unsaturated Thioamides

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(24)

Published: April 22, 2023

Herein, a copper(I)-catalyzed asymmetric conjugate addition/protonation with selenols and α-substituted α,β-unsaturated thioamides is disclosed, which affords series of chiral selenides in high to excellent enantioselectivity. As for both thioamides, the reaction enjoys broad substrate scopes. The present catalytic system also successfully applied selenation β-substituted thioamides. A [Cu-(R,RP )-TANIAPHOS]-SePh species characterized by its 77 Se NMR spectra, gives chemical shift at δ 462 ppm. Moreover, {[Cu-(R)-TOL-BINAP]-SePh}2 X-ray analysis, confirms formation Cu-Se bond reaction. Finally, transformations thioamide group amine thioester are demonstrated be straightforward.

Language: Английский

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Metal Free Functionalization of Saturated Heterocycles with Vinylarenes and Pyridine Enabled by Photocatalytic Hydrogen Atom Transfer

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(31)

Published: April 3, 2024

Abstract Saturated heterocycles are important class of structural scaffolds in small‐molecule drugs, natural products, and synthetic intermediates. Here, we disclosed a metal free, mild, scalable functionalization saturated using vinylarenes as linchpin approach. Key to success this transformation is the employing simple cheap benzophenone hydrogen atom transfer (HAT) catalyst. This operationally robust process was used for making diverse functionalized heterocycles. Furthermore, aldehydes, alkane, alcohol have been under optimized conditions. The potential pharmaceutical utility procedure has also demonstrated by late‐stage bioactive compounds molecules. Initial mechanism studies control experiments were performed elucidate reactions

Language: Английский

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