Direct deoxygenative borylation of carboxylic acids DOI Creative Commons
Jianbin Li, Chia‐Yu Huang, Mohamad Ataya

et al.

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: Aug. 17, 2021

Abstract Carboxylic acids are readily available, structurally diverse and shelf-stable; therefore, converting them to the isoelectronic boronic acids, which play pivotal roles in different settings, would be highly enabling. In contrast well-recognised decarboxylative borylation, chemical space of carboxylic-to-boronic acid transformation via deoxygenation remains underexplored due thermodynamic kinetic inertness carboxylic C-O bonds. Herein, we report a deoxygenative borylation reaction free or their sodium salts synthesise alkylboronates under metal-free conditions. Promoted by uniquely Lewis acidic strongly reducing diboron reagent, bis(catecholato)diboron (B 2 cat ), library aromatic converted benzylboronates. By leveraging same borylative manifold, facile triboration process with aliphatic is also realised, diversifying pool available 1,1,2-alkyl(trisboronates) that were otherwise difficult access. Detailed mechanistic studies reveal stepwise cleavage profile, could inspire encourage future endeavours on more appealing reductive functionalisation oxygenated feedstocks.

Language: Английский

Generation of non-stabilized alkyl radicals from thianthrenium salts for C–B and C–C bond formation DOI Creative Commons
Cheng Chen,

Zhengjun Wang,

Hongjian Lu

et al.

Nature Communications, Journal Year: 2021, Volume and Issue: 12(1)

Published: July 26, 2021

Abstract Sulfonium salts bearing a positively charged sulfur atom with three organic substituents have intrigued chemists for more than century their unusual structures and high chemical reactivity. These compounds are known to undergo facile single-electron reduction emerge as valuable alternative source of aryl radicals synthesis. However, the generation non-stabilized alkyl from sulfonium has been challenge several decades. Here we report treatment S -(alkyl) thianthrenium generate key intermediates granting controlled selective outcome ensuing reactions under mild photoredox conditions. The value these reagents demonstrated through efficient construction alkylboronates other transformations, including heteroarylation, alkylation, alkenylation, alkynylation. developed method is practical, provides opportunity convert C–OH bond C–B C–C bonds.

Language: Английский

Citations

127
Ligand-Enabled “Two-in-One” Metallaphotocatalytic Cross Couplings DOI
Jianbin Li, Ding Zhang, Zheng Hu

et al.

ACS Catalysis, Journal Year: 2025, Volume and Issue: 15(3), P. 1635 - 1654

Published: Jan. 15, 2025

Metallaphotoredox cross coupling (MCC) is ranking among the most advanced synthetic methodology as it can access chemical space that difficult to attain under conventional conditions. Earlier developed MCC mandates an independent transition metal catalyst and respective photocatalyst, thus constituting a dual catalytic manifold. Complementarily, paradigm-shifting metallaphotoredox strategy capitalizes on single photoreactive complex emerging, which brings not only operational simplification but also unexpected mechanistic insights. This perspective compiled recent advances in monocatalytic couplings categorized them based ligands confer distinct photoreactivities various mechanisms. To this end, ligand-enabled oxidative addition, transmetalation, reductive elimination other radical-involving pathways were summarized with notable examples. In way, we wish provide handy guideline for readers who are interested emerging field inspire more future endeavors MCCs beyond.

Language: Английский

Citations

3
Green chemistry meets medicinal chemistry: a perspective on modern metal-free late-stage functionalization reactions DOI
Juan D. Lasso, Durbis J. Castillo‐Pazos, Chao‐Jun Li

et al.

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(19), P. 10955 - 10982

Published: Jan. 1, 2021

This review summarizes the most recent advances of metal-free late-stage functionalization (LSF) pharmaceutically relevant molecules. Particular emphasis is placed on C – H activation as well use endogenous functional groups.

Language: Английский

Citations

103
Photo-induced thiolate catalytic activation of inert Caryl-hetero bonds for radical borylation DOI Creative Commons
Shun Wang, Hua Wang,

Burkhard König

et al.

Chem, Journal Year: 2021, Volume and Issue: 7(6), P. 1653 - 1665

Published: May 28, 2021

Language: Английский

Citations

80
Transient Imine as a Directing Group for the Metal-Free o-C–H Borylation of Benzaldehydes DOI
Supriya Rej, Naoto Chatani

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(7), P. 2920 - 2929

Published: Feb. 15, 2021

Organoboron reagents are important synthetic intermediates and have wide applications in organic chemistry. The selective borylation strategies that currently use largely rely on the of transition-metal catalysts. Hence, identifying much milder conditions for transition-metal-free would be highly desirable. We herein present a unified strategy C–H electron-deficient benzaldehyde derivatives using simple metal-free approach, utilizing an imine transient directing group. covers spectrum reactions (i) even sterically hindered bonds can borylated smoothly, (ii) despite presence other potential groups, reaction selectively occurs at o-C–H bond moiety, (iii) natural products appended to also give appropriate products. Moreover, efficacy protocol was confirmed by fact proceeds series external impurities.

Language: Английский

Citations

65
Deoxygenative Functionalizations of Aldehydes, Ketones and Carboxylic Acids DOI
Jianbin Li, Chia‐Yu Huang, Chao‐Jun Li

et al.

Angewandte Chemie International Edition, Journal Year: 2021, Volume and Issue: 61(10)

Published: Nov. 15, 2021

The simple and efficient conversion of carbonyl compounds into functionalized alkanes via deoxygenation is highly enabling in chemical synthesis. This Review covers the recent methodology development carboxyl deoxygenative functionalizations, highlighting some representative significant contributions this field. These advances are categorized based on reactivity patterns oxygenated feedstock compounds, including aldehydes, ketones carboxylic acids. Four types reactive intermediates arising from aldehydes during deoxygenation, namely, bis-electrophiles, carbenoids, bis-nucleophiles alkyl radical equivalents, presented, while acids mainly behave as tris-electrophiles when deoxygenated. In each subcategory, selected examples organized according to type bond formation discussed a generalized mechanistic perspective.

Language: Английский

Citations

62
Development of a Quinolinium/Cobaloxime Dual Photocatalytic System for Oxidative C–C Cross-Couplings via H2 Release DOI
Jianbin Li, Chia‐Yu Huang, Jing‐Tan Han

et al.

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(22), P. 14148 - 14158

Published: Nov. 8, 2021

Designing molecular photocatalysts for potent photochemical reactivities ranks among the most challenging but rewarding endeavors in synthetic photochemistry. Herein, we document a quinoline-based organophotoredox catalyst, 2,4-bis(4-methoxyphenyl)quinoline (DPQN2,4-di-OMe), that could be assembled via facile aldehyde–alkyne–amine (A3) couplings. Unlike reported photocatalysts, which impart their photoreactivities as covalently linked entities, our mechanistic studies suggested distinct proton activation mode of DPQN2,4-di-OMe. Simply upon protonation, DPQN2,4-di-OMe reach highly oxidizing excited state under visible-light irradiation (E*1/2 = +1.96 V vs standard calomel electrode, SCE). On this basis, synergistic merger and cobaloxime formulated an oxidative cross-coupling platform, enabling Minisci alkylation various C–C bond-forming reactions with diverse pool radical precursors absence chemical oxidants. The catalytic loading minimized to 0.025 mol % (TON 3360), polymer-supported photocatalyst, DPQN2,4-di-OR@PS, was prepared facilitate catalyst recycling (at 0.50 mmol up five times without significant loss photosynthetic efficiency).

Language: Английский

Citations

59
Catalysis with Diboron(4)/Pyridine: Application to the Broad-Scope [3 + 2] Cycloaddition of Cyclopropanes and Alkenes DOI
Zhengwei Ding, Zhi Liu, Zhijun Wang

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(19), P. 8870 - 8882

Published: May 9, 2022

In contrast to the extensive but non-recyclable use of tetraalkoxydiboron(4) compounds as stoichiometric reagents in diverse reactions, this article reports an atom-economical reaction using a commercial diboron(4) catalyst. The key success was designing catalytic cycle for radical [3 + 2] cycloaddition involving pyridine cocatalyst generate from catalyst and reversibly mediate transfer boronyl radicals. comparison with known transition metal-based catalysts, current features not only metal-free conditions, inexpensive stable simple operation also remarkably broadened substrate scope. particular, previously unusable cyclopropyl ketones without activating group and/or alkenes 1,2-disubstitution 1,1,2-trisubstitution patterns were successfully used first time. Consequently, challenging cyclopentane various levels substitution (65 examples, 57 new products, up six substituents at all five ring atoms) readily prepared generally high excellent yield diastereoselectivity. applied concise formal synthesis anti-obesity drug building natural product-like complex bridged or spirocyclic compounds. Mechanistic experiments computational investigation support proposed relay catalysis featuring pyridine-assisted Overall, work demonstrates approach catalysts may lead development new, green, efficient metal-like boron-catalyzed organic reactions.

Language: Английский

Citations

59
Two-in-one metallaphotoredox cross-couplings enabled by a photoactive ligand DOI Creative Commons
Jianbin Li, Chia‐Yu Huang, Chao‐Jun Li

et al.

Chem, Journal Year: 2022, Volume and Issue: 8(9), P. 2419 - 2431

Published: June 9, 2022

Language: Английский

Citations

45
Copper-Mediated Dehydrogenative C(sp3)–H Borylation of Alkanes DOI Creative Commons
Ruocheng Sang, Wangyujing Han, Hanwen Zhang

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(28), P. 15207 - 15217

Published: July 6, 2023

Borylations of inert carbon-hydrogen bonds are highly useful for transforming feedstock chemicals into versatile organoboron reagents. Catalysis these reactions has historically relied on precious-metal complexes, which promote dehydrogenative borylations with diboron reagents under oxidant-free conditions. Recently, photoinduced radical-mediated involving hydrogen atom transfer pathways have emerged as attractive alternatives because they provide complimentary regioselectivities and proceed metal-free However, net oxidative processes require stoichiometric oxidants therefore cannot compete the high economy their precious-metal-catalyzed counterparts. Herein, we report that CuCl2 catalyzes radical-mediated, C(sp3)-H alkanes bis(catecholato)diboron This is a result an unexpected dual role copper catalyst, promotes oxidation reagent to generate electrophilic bis-boryloxide acts effective borylating agent in subsequent redox-neutral photocatalytic C-H borylations.

Language: Английский

Citations

39