Photoredox‐Catalyzed α−C−H Monoalkylation of Symmetric Polyols in the Presence of CO2 DOI

Gaétan Archer,

Ricardo Meyrelles,

Isabel Eder

et al.

Angewandte Chemie, Journal Year: 2023, Volume and Issue: 136(6)

Published: Dec. 13, 2023

Abstract Achieving the selective modification of symmetric poly‐hydroxylated compounds presents a significant challenge due to presence identical active sites. Herein, we address this through design ternary catalytic system that includes photoredox catalyst, hydrogen atom transfer promotor and carbonation catalyst. This enables reversible acyclic polyols under CO 2 atmosphere, which modulates reactivity its distinct C−H bonds toward transfers. An exquisite selectivity for monoalkylation is achieved in variety unprotected light polyols, yielding valuable building blocks short reaction times. Mechanistic computational studies demonstrate formation an intramolecular bond between transient carbonate free alcohol pivotal kinetic thermodynamic activation specific alcohol.

Language: Английский

Transformations of carbohydrate derivatives enabled by photocatalysis and visible light photochemistry DOI Creative Commons

Daniel J. Gorelik,

Shrey P. Desai,

Sofia Jdanova

et al.

Chemical Science, Journal Year: 2024, Volume and Issue: 15(4), P. 1204 - 1236

Published: Jan. 1, 2024

This review article highlights the diverse ways in which recent developments areas of photocatalysis and visible light photochemistry are impacting synthetic carbohydrate chemistry.

Language: Английский

Citations

30
Titanium in photocatalytic organic transformations: current applications and future developments DOI
Jia‐Lin Tu, Binbin Huang

Organic & Biomolecular Chemistry, Journal Year: 2024, Volume and Issue: 22(33), P. 6650 - 6664

Published: Jan. 1, 2024

Titanium, as an important transition metal, has garnered extensive attention in both industry and academia due to its excellent mechanical properties, corrosion resistance, unique reactivity organic synthesis. In the field of photocatalysis, titanium-based compounds such titanium dioxide (TiO

Language: Английский

Citations

6
The sugar cube: Network control and emergence in stereoediting reactions DOI
Hayden M. Carder, Gino Occhialini, Giovanni Bistoni

et al.

Science, Journal Year: 2024, Volume and Issue: 385(6707), P. 456 - 463

Published: July 25, 2024

Stereochemical editing strategies have recently enabled the transformation of readily accessible substrates into rare and valuable products. Typically, site selectivity is achieved by minimizing kinetic complexity using protecting groups to suppress reactivity at undesired sites (substrate control) or catalysts with tailored shapes drive desired (catalyst control). We propose "network control," a contrasting paradigm that exploits hidden interactions between rate constants greatly amplify modest intrinsic biases enable precise multisite editing. When network control applied photochemical isomerization hexoses, six eight possible diastereomers can be selectively obtained. The amplification effect viewed as mesoscale phenomenon limiting regimes in simple chemical systems metabolic regulation complex biological systems.

Language: Английский

Citations

5
Competition between C–C and C–H Bond Fluorination: A Continuum of Electron Transfer and Hydrogen Atom Transfer Mechanisms DOI
Muyuan Wang,

Rozhin Rowshanpour,

Liangyu Guan

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(41), P. 22442 - 22455

Published: Oct. 4, 2023

In 2015, we reported a photochemical method for directed C-C bond cleavage/radical fluorination of relatively unstrained cyclic acetals using Selectfluor and catalytic 9-fluorenone. Herein, provide detailed mechanistic study this reaction, during which it was discovered that the key electron transfer step proceeds through substrate oxidation from Selectfluor-derived N-centered radical intermediate (rather than initially suspected photoinduced transfer). This finding led to proof concept two new methodologies, demonstrating can also be achieved under chemical electrochemical conditions. Moreover, as C-H reactions are both theoretically possible on 2-aryl-cycloalkanone would involve same reactive intermediate, studied competition between single-electron (SET) apparent hydrogen-atom (HAT) pathways in acetal density functional theory. Finally, these analyses were applied more broadly other classes developed over past decade, addressing feasibility SET processes masquerading HAT literature.

Language: Английский

Citations

11
Reactivity of Alcohol Substrates and Boron-Containing Complexes in C–H Alkylation Enabled by Photoredox, Hydrogen Atom Transfer, and Boronic Acid Catalysis DOI

Seth Christopher Cowan,

Courtney D. Glenn,

Mason D. Hamilton

et al.

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

Published: May 21, 2025

Using boronic acid, photoredox, and HAT catalysis, the relative alkylation reactivity of representative alkyl alcohols was evaluated through competition experiments, revealing higher initial for diols. Electron-poor arylboronic acid catalysts provide increased reaction efficiency all substrates, which is attributed to a more dynamic facile equilibrium between boron-containing species. Furthermore, β-carboxyboronic acids resulted in an additional increase efficiency, results from both catalyst classes were compared using kinetic profiles select scope monoalcohols.

Language: Английский

Citations

0
Asymmetric Pd/Organoboron‐Catalyzed Site‐Selective Carbohydrate Functionalization with Alkoxyallenes Involving Noncovalent Stereocontrol DOI Creative Commons
Hao Guo, Jan‐Lukas Kirchhoff, Carsten Strohmann

et al.

Angewandte Chemie, Journal Year: 2024, Volume and Issue: 136(21)

Published: March 26, 2024

Abstract Herein, we demonstrate the robustness of a synergistic chiral Pd/organoboron system in tackling challenging suite site‐, regio‐, enantio‐ and diastereoselectivity issues across considerable palette biologically relevant carbohydrate polyols, when prochiral alkoxyallenes were employed as electrophiles. In view burgeoning role noncovalent interactions (NCIs) stereoselective synthesis, our mechanistic experiments DFT modeling reaction path unexpectedly revealed that NCIs such hydrogen bonding CH‐π between resting states Pd‐π‐allyl complex borinate saccharide are critically involved stereoselectivity control. Our strategy thus illuminates untapped potential harnessing context transition metal catalysis to tackle challenges functionalization.

Language: Английский

Citations

3
Asymmetric Pd/Organoboron‐Catalyzed Site‐Selective Carbohydrate Functionalization with Alkoxyallenes Involving Noncovalent Stereocontrol DOI Creative Commons
Hao Guo, Jan‐Lukas Kirchhoff, Carsten Strohmann

et al.

Angewandte Chemie International Edition, Journal Year: 2024, Volume and Issue: 63(21)

Published: March 26, 2024

Abstract Herein, we demonstrate the robustness of a synergistic chiral Pd/organoboron system in tackling challenging suite site‐, regio‐, enantio‐ and diastereoselectivity issues across considerable palette biologically relevant carbohydrate polyols, when prochiral alkoxyallenes were employed as electrophiles. In view burgeoning role noncovalent interactions (NCIs) stereoselective synthesis, our mechanistic experiments DFT modeling reaction path unexpectedly revealed that NCIs such hydrogen bonding CH‐π between resting states Pd‐π‐allyl complex borinate saccharide are critically involved stereoselectivity control. Our strategy thus illuminates untapped potential harnessing context transition metal catalysis to tackle challenges functionalization.

Language: Английский

Citations

3
Synthesis of branched-chain sugars and higher-carbon sugars enabled by site-selective C–H alkylation relying on 1,5-hydrogen atom transfer of ethylenoxy radicals DOI
Dongwei Li,

Lingjun Wang,

Jianjun Wang

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(5), P. 1332 - 1340

Published: Jan. 1, 2024

Branched-chain sugars and higher-carbon have been efficiently prepared by site-selective C–H alkylation mediated 1,5-HAT of ethylenoxy radicals.

Language: Английский

Citations

2
Origin of site-selectivity of hydrogen atom transfer in carbohydrate C–H alkylations via photoredox catalysis DOI
Yujie Ji,

Lingfei Hu,

Han Gao

et al.

Organic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(8), P. 2269 - 2276

Published: Jan. 1, 2024

Two major factors, i.e. , C–H σ orbital energy and BDE, account for the HAT site-selectivity of carbohydrates with quinuclidine radical cation.

Language: Английский

Citations

1
Recent Progress in the Synthesis and Glycosylation of Rare Sugars DOI Creative Commons
Nicole Hauser, Marvin Wenninger,

Martin L. Poulsen

et al.

Synthesis, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 8, 2024

Abstract Out of 42 naturally occurring monosaccharides, only seven are abundant in Nature (glucose, galactose, mannose, fructose, xylose, ribose, and l-arabinose), while the others have been classified as ‘rare sugars’. Fungi bacteria use a wide range contrast to mammals, reflected their glycosylated metabolites, well cellular machineries that involved sugar metabolism. Recognition microbiome’s impact on human health has led increased interest microbial glycans, they often mediate interaction between host microbes. Efficient access rare sugars oligosaccharides is necessary study roles Nature, which can provide new pharmacological leads. Furthermore, it enables synthesis bioactive natural products congeners. This short review highlights recent progress efficient, site- stereoselective glycosylation sugars. Finally, provides example where synthetic enabled biochemical studies better understand interfere with processes Nature. 1 Introduction 2 Synthesis Rare Sugars 2.1 Syntheses from Renewable Feedstock 2.2 De Novo 3 Glycosylation 3.1 Catalyst-Controlled 3.2 One-Pot Iterative Oligosaccharide Solution 4 Application Biochemical Research 5 Conclusion

Language: Английский

Citations

1