Sustainable Photooxidation using a Subpart-per-million Heavy-Metal-Free Red-Light Photocatalyst DOI
Maxime Lancel,

Tamara Golisano,

Cyrille Monnereau

et al.

ACS Sustainable Chemistry & Engineering, Journal Year: 2023, Volume and Issue: 11(43), P. 15674 - 15684

Published: Oct. 15, 2023

Photochemical activation using red or near-infrared light has recently emerged as a potential remedy for solving fundamental issues in photochemistry such selectivity and scale up. However, this is particularly challenging the case of photooxidation chemistry due to low resistance photobleaching poor solubility photocatalysts absorbing region electromagnetic spectrum. In study, we report use commercially available Si-phthalocyanines robust environmentally friendly class soluble photosensitizers activated under light. Interestingly, while exhibit lower singlet oxygen generation (ϕΔ) quantum yields compared classical photosensitizers, their high stability enables us achieve comparable efficiencies at ultralow catalytic loadings (ppb range). This unique feature provides performances range photooxidative processes substrate concentrations ultimately leading safe efficient solvent-free continuous flow applied multigram-scale synthesis.

Language: Английский

Multiplicative enhancement of stereoenrichment by a single catalyst for deracemization of alcohols DOI
Lu Wen, Jia Ding, Lingfei Duan

et al.

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

Citations

63
Asymmetric Cross-Coupling of Aldehydes with Diverse Carbonyl or Iminyl Compounds by Photoredox-Mediated Cobalt Catalysis DOI

Zhiyong Chi,

Jia-Bin Liao,

Xiuliang Cheng

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(15), P. 10857 - 10867

Published: April 8, 2024

The asymmetric cross-coupling of unsaturated bonds, hampered by their comparable polarity and reactivity, as well the scarcity efficient catalytic systems capable diastereo- enantiocontrol, presents a significant hurdle in organic synthesis. In this study, we introduce highly adaptable photochemical cobalt catalysis framework that facilitates chemo- stereoselective reductive cross-couplings between common aldehydes with broad array carbonyl iminyl compounds, including N-acylhydrazones, aryl ketones, aldehydes, α-keto esters. Our methodology hinges on synergistic mechanism driven photoredox-induced single-electron reduction subsequent radical–radical coupling, all precisely guided chiral catalyst. Various optically enriched β-amino alcohols unsymmetrical 1,2-diol derivatives (80 examples) have been synthesized good yields (up to 90% yield) high stereoselectivities >20:1 dr, 99% ee). Of particular note, approach accomplishes unattainable transformations disparate partners without reliance any external photosensitizer, thereby further emphasizing its versatility cost-efficiency.

Language: Английский

Citations

17
Photocatalytic Metal Hydride Hydrogen Atom Transfer Mediated Allene Functionalization by Cobalt and Titanium Dual Catalysis DOI

Huaipu Yan,

Qian Liao, Yuqing Chen

et al.

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

Published: April 12, 2023

Catalytic metal hydride hydrogen atom transfer (MHAT) reactions have proven to be a powerful method for alkene functionalization. This work reports the discovery of Co-porphines as highly efficient MHAT catalysts with loading only 0.01 mol % unprecedented chemoselective allene functionalization under photoirradiation. Moreover, newly developed bimetallic strategy by combination photo Co-MHAT and Ti catalysis enabled successful carbonyl allylation wide range amino, oxy, thio, aryl, alkyl-allenes providing expedient access valuable β-functionalized homoallylic alcohols in over 100 examples exceptional regio- diastereoselectivity. Mechanism studies DFT calculations supported that selectively transferring atoms from cobalt allenes generating allyl radicals is key step catalytic cycle.

Language: Английский

Citations

27
Low-energy photoredox catalysis DOI
David C. Cabanero, Tomislav Rovis

Nature Reviews Chemistry, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 11, 2024

Language: Английский

Citations

10
Visible-Light-Antenna Ligand-Enabled Samarium-Catalyzed Reductive Transformations DOI
Takahito Kuribara,

Ayahito Kaneki,

Yu Matsuda

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(30), P. 20904 - 20912

Published: July 20, 2024

Although divalent Sm reagents are some of the most important single-electron transfer for reductive transformations, their catalytic applications challenging. In this study, a bidentate phosphine oxide ligand substituted with 9,10-diphenylanthracene as visible-light antenna was designed Sm-catalyzed reduction reactions under mild reaction conditions. Pinacol coupling aryl ketones and aldehydes developed 1 mol % catalyst organic amine (DIPEA) sacrificial reductant. Mechanistic studies suggest that visible-light-antenna coordinates to Sm(III) reduces Sm(II) irradiation. The system is also applicable cross-pinacol other including aza-pinacol coupling, flavone dimerization, C-O bond cleavage, C-C ring-opening cyclopropane, ketyl-olefin cross-coupling ketyl radical α-amino radical.

Language: Английский

Citations

9
Photoinduced generation of ketyl radicals and application in C–C coupling withoutexternal photocatalyst DOI
Y. Yan, Gang Li, Jiani Ma

et al.

Green Chemistry, Journal Year: 2023, Volume and Issue: 25(10), P. 4129 - 4136

Published: Jan. 1, 2023

A green and efficient procedure for photoinduced generation of ketyl radicals with no use any external photocatalyst is demonstrated, enabling a series important C–C coupling reactions in synthetic chemistry.

Language: Английский

Citations

22
Red-Shifting Blue Light Photoredox Catalysis for Organic Synthesis: A Graphical Review DOI Creative Commons
Tomislav Rovis, Logan R. Beck,

Katherine A. Xie

et al.

SynOpen, Journal Year: 2023, Volume and Issue: 07(01), P. 76 - 87

Published: Feb. 1, 2023

Abstract Photoredox catalysis has revolutionized synthetic chemistry in recent decades. However, the field traditionally used high-energy blue/ultraviolet light to activate chromophores. High-energy irradiation is associated with several drawbacks (e.g., activation of sensitive functional groups, undesired metal-ligand homolysis, background molecules, and poor penetration), which led researchers develop alternative systems lower energy deep red (DR) or near-infrared (NIR) light. This graphical review provides a concise overview photophysical principles relevant photoredox catalysis. Several applications that benefit from low-energy irradiation, such as large-scale batch reactions, photodynamic therapy, biological labeling, multi-photon excitation are reviewed.

Language: Английский

Citations

17
Recent Advances in Visible Light‐induced Asymmetric Transformations of Carbonyl Compounds into Chiral Alcohols DOI
Liuzhen Hou, Xiaohua Liu, Weidi Cao

et al.

ChemCatChem, Journal Year: 2023, Volume and Issue: 15(21)

Published: Aug. 16, 2023

Abstract Visible light‐induced photocatalysis has been widely investigated, which offers exciting opportunities to build new catalytic platforms that are unattainable under ground state conditions. Asymmetric a longstanding challenge due the high reactivity of photogenerated intermediates leading strong background reaction. Carbonyl group is an important fundamental scaffold in organic synthesis. The photocatalytic asymmetric transformations carbonyl compounds for synthesizing enantioenriched secondary and tertiary alcohols significant value but remain problematic. Even so, series intriguing works concerning this topic have reported recent year. This review summarizes advances area, mainly dividing into single synergetic catalyst systems, mechanism each reaction discussed.

Language: Английский

Citations

17
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
Light-Induced Access to Carbazole-1,3-dicarbonitrile: A Thermally Activated Delayed Fluorescent (TADF) Photocatalyst for Cobalt-Mediated Allylations DOI Creative Commons
Emanuele Pinosa, Elena Bassan, Sultan Cetin

et al.

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 88(10), P. 6390 - 6400

Published: Nov. 16, 2022

The stability of a photocatalyst under irradiation is important in photoredox applications. In this work, we investigated the thermally activated delayed fluorescence (TADF) {3DPAFIPN [2,4,6-tris(diphenylamino)-5-fluoroisophthalonitrile]}, recently employed photoredox-mediated processes, discovering that absence quenchers chromophore unstable and efficiently converted by with visible light into another species based on carbazole-1,3-dicarbonitrile moiety. new obtained itself TADF emitter finds useful applications transformations. At excited state, it strong reductant was applied to cobalt-mediated allylation aldehydes, whereas other TADFs (4CzIPN 3DPAFIPN) failed promote efficient photocatalytic cycles.

Language: Английский

Citations

26