Recent Advances in Employing Catalytic Donors and Acceptors in Electron Donor–Acceptor Complex Photochemistry

The Journal of Organic Chemistry, Год журнала: 2022, Номер 87(16), С. 10555 - 10563

Опубликована: Июль 29, 2022

Electron donor–acceptor (EDA) complexes provide a means to initiate radical reactions under visible light irradiation using substrates that do not absorb individually. Catalytic approaches complex formation are vital for advancing this synthetic strategy as it decouples the complexation and photogeneration of radicals from substrate functionalization, limitation inherent stoichiometric restricts structural diversity. This Synopsis highlights recent developments in EDA photochemistry which either donor or acceptor employed catalytically.

Язык: Английский

---

Stereoselective amino acid synthesis by synergistic photoredox-pyridoxal radical biocatalysis

Science, Год журнала: 2023, Номер 381(6656), С. 444 - 451

Опубликована: Июль 27, 2023

Developing synthetically useful enzymatic reactions that are not known in biochemistry and organic chemistry is an important challenge biocatalysis. Through the synergistic merger of photoredox catalysis pyridoxal 5'-phosphate (PLP) biocatalysis, we developed a radical biocatalysis approach to prepare valuable noncanonical amino acids, including those bearing stereochemical dyad or triad, without need for protecting groups. Using engineered PLP enzymes, either enantiomeric product could be produced biocatalyst-controlled fashion. Synergistic

Язык: Английский

---

Using enzymes to tame nitrogen-centred radicals for enantioselective hydroamination

Nature Chemistry, Год журнала: 2022, Номер 15(2), С. 206 - 212

Опубликована: Ноя. 14, 2022

Язык: Английский

---

Tetrachlorophthalimides as Organocatalytic Acceptors for Electron Donor–Acceptor Complex Photoactivation

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(20), С. 8914 - 8919

Опубликована: Май 13, 2022

Excitation of photoactive electron donor-acceptor (EDA) complexes is an effective way to generate radicals. Applications in a catalytic regime typically use donors. Herein, we report that readily available electron-poor tetrachlorophthalimides can act as organocatalytic acceptors trigger the formation EDA with variety radical precursors not amenable previous methods. visible light generates carbon radicals under mild conditions. The versatility this complex platform allowed us develop mechanistically distinct reactions, including combination cobalt-based system. Quantum yield measurements established closed cycle operational, which hints at ability turn over and govern each cycle.

Язык: Английский

---

Single-Electron Oxidation-Initiated Enantioselective Hydrosulfonylation of Olefins Enabled by Photoenzymatic Catalysis

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(4), С. 2748 - 2756

Опубликована: Янв. 12, 2024

Controlling the enantioselectivity of hydrogen atom transfer (HAT) reactions has been a long-standing synthetic challenge. While recent advances on photoenzymatic catalysis have demonstrated great potential non-natural photoenzymes, all transformations are initiated by single-electron reduction substrate, with only one notable exception. Herein, we report an oxidation-initiated enantioselective hydrosulfonylation olefins using novel mutant gluconobacter ene-reductase (GluER-W100F-W342F). Compared to known systems, our approach does not rely formation electron donor–acceptor complex between substrates and enzyme cofactor simplifies reaction system obviating addition regeneration mixture. More importantly, GluER variant exhibits high reactivity broad substrate scope. Mechanistic studies support proposed mechanism reveal that tyrosine-mediated HAT process is involved.

Язык: Английский

---

Stereoselective amino acid synthesis by photobiocatalytic oxidative coupling

Nature, Год журнала: 2024, Номер 629(8010), С. 98 - 104

Опубликована: Май 1, 2024

Язык: Английский

---

From Ground-State to Excited-State Activation Modes: Flavin-Dependent “Ene”-Reductases Catalyzed Non-natural Radical Reactions

Accounts of Chemical Research, Год журнала: 2024, Номер 57(9), С. 1446 - 1457

Опубликована: Апрель 11, 2024

ConspectusEnzymes are desired catalysts for chemical synthesis, because they can be engineered to provide unparalleled levels of efficiency and selectivity. Yet, despite the astonishing array reactions catalyzed by natural enzymes, many reactivity patterns found in small molecule have no counterpart living world. With a detailed understanding mechanisms utilized catalysts, we identify existing enzymes with potential catalyze that currently unknown nature. Over past eight years, our group has demonstrated flavin-dependent "ene"-reductases (EREDs) various radical-mediated selectivity, solving long-standing challenges asymmetric synthesis.This Account presents development EREDs as general radical reactions. While developed multiple generating radicals within protein active sites, this account will focus on examples where flavin mononucleotide hydroquinone (FMNhq) serves an electron transfer initiator. initial mechanistic hypotheses were rooted electron-transfer-based initiation commonly used synthetic organic chemists, ultimately uncovered emergent unique site. We begin covering intramolecular discussing how activates substrate reduction altering redox-potential alkyl halides templating charge complex between flavin-cofactor. Protein engineering been modify fundamental photophysics these reactions, highlighting opportunity tune systems further using directed evolution. This section highlights range coupling partners termination available reactions.The next intermolecular role enzyme-templated ternary complexes among cofactor, halide, partner gating ensure it only occurs when both substrates bound highlight applications activation mode, including olefin hydroalkylation, carbohydroxylation, arene functionalization, nitronate alkylation. also discusses favor steps elusive solution reductive nitroalkanes. aware several recent EREDs-catalyzed photoenzymatic transformations from other groups. discuss results papers context nuances substrates.These biocatalytic often complement state-of-the-art small-molecule-catalyzed making valuable addition chemist's toolbox. Moreover, underlying principles studied potentially operative cofactor-dependent proteins, opening door different types enzyme-catalyzed anticipate serve guide inspire broad interest repurposing access new transformations.

Язык: Английский

---

Stereodivergent photobiocatalytic radical cyclization through the repurposing and directed evolution of fatty acid photodecarboxylases

Nature Chemistry, Год журнала: 2024, Номер 16(8), С. 1339 - 1347

Опубликована: Апрель 17, 2024

Язык: Английский

---

Photoenzymatic Synthesis of α-Tertiary Amines by Engineered Flavin-Dependent “Ene”-Reductases

Journal of the American Chemical Society, Год журнала: 2021, Номер 143(47), С. 19643 - 19647

Опубликована: Ноя. 16, 2021

α-Tertiary amines are a common motif in pharmaceutically important molecules but challenging to prepare using asymmetric catalysis. Here, we demonstrate engineered flavin-dependent 'ene'-reductases (EREDs) can catalyze radical additions into oximes this motif. Two different EREDs were evolved competent catalysts for transformation with high levels of stereoselectivity. Mechanistic studies indicate that the oxime contributes enzyme templated charge-transfer complex formed between substrate and cofactor. These products be further derivatized variety motifs, highlighting versatility ERED photoenzymatic catalysis organic synthesis.

Язык: Английский

---

Enzymatic strategies for asymmetric synthesis

RSC Chemical Biology, Год журнала: 2021, Номер 2(4), С. 958 - 989

Опубликована: Янв. 1, 2021

Asymmetric synthesis achieved with enzymes for stereoselective reduction and bond forming reactions, enantioselective atroposelective reactions.

Язык: Английский

---