Green Synthesis of 1,4-Dihydropyridines through Catalyst-Free Multicomponent Hantzsch Reaction in an Undergraduate Teaching Laboratory DOI
Yan Zhang,

Xiuya Ma,

Xinyu Zhou

et al.

Journal of Chemical Education, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 27, 2025

Multicomponent reactions (MCRs) are fascinating chemical processes where three or more starting materials come together to form a single product. By exploring various MCRs, second-year undergraduate students learn about the synergy between different functional groups and how they influence reactivity, power of streamlined approach compared conventional stepwise reactions, critical thinking MCR mechanisms. Herein, we introduce valuable synthetic method for constructing heterocyclic compounds through multiple-component condensation/cycloaddition process. Specifically, focus on 1,4-dihydropyridine (1,4-DHP), privileged N-heterocyclic scaffold widely used in medicinal chemistry, particularly 4-aryl-3,5-dicarboxylated derivatives. The experiment provides an excellent opportunity explore concept green chemistry while synthesizing structurally interesting useful molecules using readily available materials. achieve this condensation reaction 2-furaldehyde (furfural), acetoacetic acid tert-butyl ester, ammonium acetate. Key features teaching include following. (1) reaction: involves concise, multicomponent with short time. (2) Catalyst-free: Notably, proceeds without need solvents catalysts. (3) Visually striking system: change system is visually evident, enhancing learning experience. (4) Useful methodology drug synthesis: has practical implications synthesis. We successfully implemented proposal across five parallel student groups, involving approximately 150 participants. experimental procedures encompass organic synthesis, thin-layer chromatography (TLC), nuclear magnetic resonance (NMR) analysis.

Language: Английский

Photoredox/Cr-catalyzed enantioselective radical-polar crossover transformation via C-H functionalization DOI Creative Commons
Siyuan Tang,

Z. Z. Wang,

Ao Yu

et al.

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: Feb. 4, 2025

Asymmetric multicomponent reactions that aim to control multiple chiral centers with high selectivity in a single step remain an on-gonging challenge. The realm of enantioselective radical-polar crossover transformation achieved through C-H Functionalization has yet be fully explored. Herein, we present successful description photoredox/Cr-catalyzed three-component (hetero)arylalkylation 1,3-dienes functionalization. A diverse array homoallylic alcohols could obtained good excellent yields, accompanied by outstanding enantioselectivity. asymmetric build two simultaneously and demonstrates broad substrate tolerance, accommodating various drug-derived aldehydes, (hetero)aromatics, 1,3-diene derivatives. Preliminary mechanistic studies indicate the involvement radical intermediate, allylic chromium species reacting aliphatic aromatic aldehydes Zimmerman–Traxler transition states enabled dual photoredox catalysis. ongoing Here, authors photoredox- chromium-catalyzed

Language: Английский

Citations

2
Asymmetric 1,4-functionalization of 1,3-enynes via dual photoredox and chromium catalysis DOI Creative Commons
Feng‐Hua Zhang,

Xiaochong Guo,

Xianrong Zeng

et al.

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Aug. 26, 2022

Abstract The merger of photoredox and transition-metal catalysis has evolved as a robust platform in organic synthesis over the past decade. stereoselective 1,4-functionalization 1,3-enynes, prevalent synthon synthetic chemistry, could afford valuable chiral allene derivatives. However, tremendous efforts have been focused on ionic reaction pathway. radical-involved asymmetric 1,3-enynes remains prominent challenge. Herein, we describe three-component 1,4-dialkylation via dual chromium to provide allenols. This method features readily available starting materials, broad substrate scope, good functional group compatibility, high regioselectivity, simultaneous control axial central chiralities. Mechanistic studies suggest that this proceeds through redox-neutral

Language: Английский

Citations

68
Enantioselective Radical Addition to Ketones through Lewis Acid-Enabled Photoredox Catalysis DOI
Liuzhen Hou, Yuqiao Zhou, Yu Han

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(48), P. 22140 - 22149

Published: Nov. 22, 2022

Photocatalysis opens up a new window for carbonyl chemistry. Despite multitude of photochemical reactions compounds, visible light-induced catalytic asymmetric transformations remain elusive and pose formidable challenge. Accordingly, the development simple, efficient, economic systems is ideal pursuit chemists. Herein, we report an enantioselective radical photoaddition to ketones through Lewis acid-enabled photoredox catalysis wherein in situ formed chiral N,N'-dioxide/Sc(III)-ketone complex serves as temporary photocatalyst trigger single-electron transfer oxidation silanes generation nucleophilic species, including primary, secondary, tertiary alkyl radicals, giving various enantioenriched aza-heterocycle-based alcohols good excellent yields enantioselectivities. The results electron paramagnetic resonance (EPR) high-resolution mass spectrum (HRMS) measurements provided favorable evidence stereocontrolled addition process involved this reaction.

Language: Английский

Citations

52
A Radical Approach for Asymmetric α-C–H Addition of N-Sulfonyl Benzylamines to Aldehydes DOI
Hui Hu,

Zhaoxin Shi,

Xiaochong Guo

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(8), P. 5316 - 5323

Published: Feb. 16, 2024

Efficient synthesis of enantioenriched amines is great importance due to their significant synthetic and biological applications. Photoredox-mediated asymmetric α-amino C(sp3)–H functionalization offers an atom-economical sustainable approach access chiral amines. However, the development analogous reactions in its early stages, generally affording with a single stereocenter. Herein, we present novel synergistic triple-catalysis for α-C–H addition readily available N-sulfonyl aldehydes under mild conditions. This method allows efficient diverse array valuable β-amino alcohols bearing vicinal stereocenters. Unlike previous reports, our protocol employs radical using earth-abundant Cr catalysis. Quinuclidine plays dual role by facilitating highly selective hydrogen-atom transfer generate radicals promoting dissociation Cr–O bond, which crucial overall catalytic cycle as evidenced control, NMR, DFT experiments. Preliminary mechanistic studies, including trapping, nonlinear effect, Stern–Volmer plot, kinetic isotope Hammett offer insights into reaction pathway.

Language: Английский

Citations

16
A modular approach to stereoselective homoaldol reaction via photoredox/Cr/Co triple catalysis DOI Creative Commons

Haigen Shen,

Zheng Zhang,

Zhaoxin Shi

et al.

Chem, Journal Year: 2024, Volume and Issue: 10(3), P. 998 - 1014

Published: Jan. 24, 2024

Language: Английский

Citations

14
Enantioselective Remote Alkylation Enabled by Metallaphotoredox Catalysis via Selective C–C Bond Cleavage DOI
Ao Yu,

Ning Wang,

Siyuan Tang

et al.

ACS Catalysis, Journal Year: 2025, Volume and Issue: 15(3), P. 2212 - 2221

Published: Jan. 23, 2025

Despite recent advances in enantioselective radical coupling with strained cyclic rings, asymmetric reactions triggered by unstrained motifs remain rare. Herein, we report a mild and general strategy for activating diverse set of readily available alcohols the remote site-specific allylic alkylation ketones through combination photoredox-mediated proton-coupled electron transfer chiral chromium catalysis. This newly developed dual catalytic system exhibits extensive applicability, operates under conditions, offers straightforward operation, demonstrates tolerance to functional groups. The open-shell has also been applied late-stage modification complex drug natural product derivatives high levels enantioselectivity.

Language: Английский

Citations

1
Spartina alterniflora biochar coupled BiOBr with dominant exposed facet and oxygen vacancies for efficiently photocatalytic degradation of ciprofloxacin DOI
Peng Ju, Shuo Yu,

Guojia Zhang

et al.

Colloids and Surfaces A Physicochemical and Engineering Aspects, Journal Year: 2025, Volume and Issue: 711, P. 136306 - 136306

Published: Jan. 31, 2025

Language: Английский

Citations

1
Radical Brook Rearrangements: Concept and Recent Developments DOI
Ying Zhang,

Junjie Chen,

Huan‐Ming Huang

et al.

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(37)

Published: June 21, 2022

The Brook rearrangement has already become established as one of the most important molecular rearrangements in synthetic chemistry and been applied generation complexes, drug discovery, material science, natural products synthesis. Compared to widely known ionic mechanism, radical is less explored because difficulty generating alkoxyl species. This Minireview summarizes early developments general concept highlights recent advances photocatalytic reactions transition-metal-catalyzed cross-coupling involving rearrangements. We hope this survey will inspire further emerging area.

Language: Английский

Citations

37
Unlocking the Nucleophilicity of Strong Alkyl C–H Bonds via Cu/Cr Catalysis DOI Creative Commons
Pan Peng,

Yifan Zhong,

Cong Zhou

et al.

ACS Central Science, Journal Year: 2023, Volume and Issue: 9(4), P. 756 - 762

Published: March 27, 2023

Direct functionalization of inert C-H bonds is one the most attractive yet challenging strategies for constructing molecules in organic chemistry. Herein, we disclose an unprecedented and Earth abundant Cu/Cr catalytic system which unreactive alkyl are transformed into nucleophilic alkyl-Cr(III) species at room temperature, enabling carbonyl addition reactions with strong bonds. Various aryl alcohols furnished under mild reaction conditions even on a gram scale. Moreover, this new radical-to-polar crossover approach further applied to 1,1-difunctionalization aldehydes alkanes different nucleophiles. Mechanistic investigations reveal that aldehyde not only acts as reactant but also serves photosensitizer recycle Cu Cr catalysts.

Language: Английский

Citations

22
Dual‐Catalysed Intermolecular Reductive Coupling of Dienes and Ketones** DOI Creative Commons

Victor J. Mayerhofer,

Martina Lippolis, Christopher J. Teskey

et al.

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 63(2)

Published: Nov. 10, 2023

Abstract We report a mild, catalytic method for the intermolecular reductive coupling of feedstock dienes and styrenes with ketones. Our conditions allow concomitant formation cobalt hydride species single‐electron reduction Subsequent selective hydrogen‐atom transfer from generates an allylic radical which can selectively couple persistent radical‐anion ketone. This radical‐radical negates unfavourable steric interactions ionic pathways avoids unstable alkoxy previous olefin‐carbonyl couplings, were limited, as result, to aldehydes. Applications this novel straightforward approach include efficient synthesis drug molecules, key intermediates in site‐selective late‐stage functionalisation.

Language: Английский

Citations

20