Controllable Chemoselectivity in Visible‐Light Photoredox Catalysis: Four Diverse Aerobic Radical Cascade Reactions

Liu, Xinfei; Ye, Xinyi; Bureš, Filip; Liu, Hongjun; Jiang, Zhiyong

doi:10.1002/ange.201505193

Cited by 29 publications

(9 citation statements)

References 57 publications

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“…As a result, with N ‐aryl itaconimides as the electrophiles, reactions with N ‐THIQs could proceed via radical‐based processes in the presence of DPZ as a catalyst under air (Scheme 5A). [ 17 ] More importantly, by simply modulating the reaction media, temperature and additives, these aerobic reactions could proceed by four distinct radical cascade pathways, namely, addition‐cyclization, addition‐elimination, addition‐coupling and addition‐protonation, with moderate to excellent chemoselectivities, leading to four kinds of valuable N ‐heterocycle derivatives in moderate to excellent yields. This work represents the first chemodivergent control of radical‐based pathways in photoredox catalysis.…”

Section: Photosensitizer Dpz In Asymmetric Photocatalysismentioning

confidence: 99%

Visible Light‐Driven Cooperative DPZ and Chiral Hydrogen‐Bonding Catalysis

Yin

et al. 2020

Chin. J. Chem.

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What is the most favorite and original chemistry developed in your research group?The visible light photosensitizer DPZ. How did you get into this specific field? Could you please share some experiences with our readers?Since I began my postdoctoral work at NUS, chiral hydrogen-bonding catalysis, an important branch of asymmetric organocatalysis, has become the general area of focus of my research. To broaden the applications of this strategy, I proposed to exploit photocatalysis to generate highly reactive radical intermediates, thus overcoming the current limitations in both reaction and substrate types stemming from the low energy of hydrogen-bonding interactions. The development of highly efficient organophotocatalysts and explorations of transition metal-free cooperative photocatalysis and chiral hydrogen-bonding catalysis have therefore been my research focus since 2013. My students and I strive to follow the saying "stick to the research direction, thoroughly understand the scientific challenges, and face those challenges with optimism and determination". What is the most important personality for scientific research?To do independent, original, ground-breaking and useful chemistry. What are your hobbies?Playing basketball, slow long distance running and reading. How do you maintain a balance between research and family?Having the understanding and support of my family is the most important thing since scientific research requires a large investment of time. Who influences you the most in your life?My parents.

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Section: Photosensitizer Dpz In Asymmetric Photocatalysismentioning

confidence: 99%

Visible Light‐Driven Cooperative DPZ and Chiral Hydrogen‐Bonding Catalysis

Yin

et al. 2020

Chin. J. Chem.

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“…84 During their study of the organocatalyzed α-arylation of benzofuran-2(3H)-ones with 1,4-naphthoquinone, Jiang and co-workers uncovered that the arylation of benzofuran-2(3H)ones 161 could also be achieved by using easily available 1naphthols 160 instead of naphthoquinones 141 as arylating agents, which underwent a photoinduced oxygenation and enantioselective Michael addition sequence (Scheme 46). 79 The desired chiral 3,3-disubstituted quaternary benzofuranones 163 featuring a naphthoquinone moiety could be obtained in moderate yields with good to excellent enantioselectivities under an oxygen atmosphere, when a combination of 4 mol % of their developed photocatalyst DPZ 85 and 20 mol % of the tertiary amine H-bonding donor catalyst 162 was employed, under irradiation of 3 W blue LED light.…”

Section: Acs Catalysismentioning

confidence: 99%

Catalytic Enantioselective α-Arylation of Carbonyl Enolates and Related Compounds

et al. 2019

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Optically active α-arylation carbonyl units are widely present in a wide variety of drugs, bioactive natural products, and valuable pharmacologically active molecules. Catalytic enantioselective α-arylation of carbonyl enolates or the related precursors with various arylating agents constitutes a powerful tactic for constructing such privileged scaffolds, which is of great interest and has gained considerable progress. This review summarizes the advances based on two major strategies with diverse arylating agents, discusses in detail the reaction mechanism, limitations, and advantages of each method and their applications, and expounds the synthetic opportunities still open for further exploration.

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“…[1][2][3] While the overall reactivity of radical intermediates is well understood, 4 catalytic strategies for controlling the chemo-and stereoselectivity remain underdeveloped. [5][6][7] Nature has evolved various biocatalysts, such as cobalamin and radical S-adenosylmethionine (SAM) enzymes, to catalyze the radical-mediated transformations with unparalleled chemo-, regio-, and enantioselectivity in the biosynthesis of complex natural products. [8][9][10][11][12] However, these enzymes are not readily harnessed outside of their natural settings by organic synthetic chemists, owing to either operational difficulties or lack of catalytic versatility.…”

Section: Introductionmentioning

confidence: 99%

Ground-State Electron Transfer as an Initiation Mechanism for Asymmetric Hydroalkylations in Radical Biocatalysis

Fu¹,

Lam²,

Emmanuel³

et al. 2021

Preprint

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Stereoselective bond-forming reactions are essential tools in modern organic synthesis. However, catalytic strategies for controlling the stereochemical outcome of radical-mediated C–C bond formation remain underdeveloped. Here, we report an ‘ene’-reductase catalyzed asymmetric hydroalkylation of olefins using α-bromoketones as radical precursors. In these reactions, radical initiation occurs via ground-state electron transfer from the flavin cofactor located within the enzyme active site, representing a mechanistic departure from previous photoenzymatic hydroalkylations. Four rounds of site saturation mutagenesis based on wild-type nicotinamide-dependent cyclohexanone reductase (NCR) were deployed to access a variant capable of catalyzing a cyclization to furnish β-chiral cyclopentanones with high levels of enantioselectivity. Additionally, the wild-type NCR was identified that could catalyze the intermolecular coupling with precise stereochemical control over the radical termination step. This report demonstrates this enzyme family’s catalytic versatility and highlights the opportunity for protein engineering to address reactivity and selectivity challenges in radical biocatalysis.

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Controllable Chemoselectivity in Visible‐Light Photoredox Catalysis: Four Diverse Aerobic Radical Cascade Reactions

Cited by 29 publications

References 57 publications

Visible Light‐Driven Cooperative DPZ and Chiral Hydrogen‐Bonding Catalysis

Visible Light‐Driven Cooperative DPZ and Chiral Hydrogen‐Bonding Catalysis

Catalytic Enantioselective α-Arylation of Carbonyl Enolates and Related Compounds

Ground-State Electron Transfer as an Initiation Mechanism for Asymmetric Hydroalkylations in Radical Biocatalysis

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