Enantioselective [2 + 2] Photocycloreversion Enables De Novo Deracemization Synthesis of Cyclobutanes

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(32), С. 22840 - 22849

Опубликована: Авг. 2, 2024

While photochemical deracemization significantly enhances atom economy by eliminating the necessity for additional oxidants or reductants, laborious presynthesis of substrates from feedstock chemicals is often required, thereby compromising practicality this method. In study, we propose a novel approach known as de novo synthesis, which involves direct utilization simple undergoing both transformation and reversible transformation. The efficient enantiocontrol chiral catalysts in latter process establishes an effective platform deracemization. This alternative practical to address challenges asymmetric photocatalysis has been successfully demonstrated photosensitized synthesis azaarene-functionalized cyclobutanes featuring three stereocenters, including all-carbon quaternary center. By exclusively employing suitable catalyst enable kinetically controlled [2 + 2] photocycloreversion, pave creative path toward achieving more cost-effective

Язык: Английский

---

Catalytic asymmetric photocycloaddition reactions mediated by enantioselective radical approaches

Chemical Society Reviews, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

The use of olefins in the construction cyclic compounds represents a powerful strategy for advancing pharmaceutical industry.

Язык: Английский

---

Orange-Light-Induced Photochemistry Gated by pH and Confined Environments

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(14), С. 6343 - 6348

Опубликована: Апрель 2, 2022

We introduce a new photochemically active compound, i.e., pyridinepyrene (PyPy), entailing pH-active moiety that effects significant halochromic shift into orange-light (λ = 590 nm) activatable photoreactivity while concomitantly exerting control over its reaction pathways. With blue light 450 in neutral to basic pH, [2 + 2] photocycloaddition can be triggered form cyclobutene ring reversible fashion. If the pH is decreased acidic conditions, resulting absorption shift, on small-molecule level blocked due repulsive interactions and exclusive trans-cis isomerization observed. Through implementation of PyPy confined environment single-chain nanoparticle (SCNP) design, one overcome forces exploit for orange nm)-induced cycloaddition formation macromolecular three-dimensional (3D) architectures.

Язык: Английский

---

Cooperative Stereoinduction in Asymmetric Photocatalysis

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(9), С. 4206 - 4213

Опубликована: Фев. 22, 2022

Stereoinduction in complex organic reactions often involves the influence of multiple stereocontrol elements. The interaction among these can result observation significant cooperative effects that afford different rates and selectivities between matched mismatched sets stereodifferentiating chiral elucidation matched/mismatched ground-state chemical was a critically important theme maturation modern stereocontrolled synthesis. development robust methods for control photochemical reactions, however, is relatively recent development, similar stereocontrolling excited-state enantioselective photoreactions have not previously been documented. Herein, we describe tandem photocatalyst/Brønsted acid strategy highly [2 + 2] photocycloadditions vinylpyridines. Importantly, catalyst pairs exhibit reaction enantioselectivities across range coupling partners. We observe no evidence interactions catalysts conclude arise from their behavior transient assembly. These results suggest might be other classes dual-catalytic reactions.

Язык: Английский

---

Ion-Pairing Catalysis in Stereoselective, Light-Induced Transformations

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(42), С. 19207 - 19218

Опубликована: Окт. 14, 2022

With the rapid development of photoredox catalysis, numerous concepts for asymmetric induction were successfully and broadly adapted from polar two-electron transformations to radical chemistry. While this applies organocatalysis or transition metal chemistry, ion-pairing catalysis remains a niche application within light-driven reactions today. This perspective gives an overview recent examples, strategies, their in stereoselective at interface photo(redox) catalysis.

Язык: Английский

---

Highly Enantioselective Radical Cation [2 + 2] and [4 + 2] Cycloadditions by Chiral Iron(III) Photoredox Catalysis

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(28), С. 15054 - 15060

Опубликована: Июль 5, 2023

Radical cations show a unique reactivity that is fundamentally different from of conventional and have thus attracted considerable attention as alternative cationic intermediates for novel types organic reactions. However, asymmetric catalysis to promote enantioselective radical cation reactions remains major challenge in contemporary synthesis. Here, we report the judicious design an ion pair consisting chiral counteranion induces excellent level enantioselectivity. This strategy was applied enantio-, diastereo-, regioselective [2 + 2] cycloadditions, well [4 by using iron(III) photoredox catalysis. We anticipate this has potential expand use several mature anions develop numerous unprecedented

Язык: Английский

---

Catalytic asymmetric [4 + 2] dearomative photocycloadditions of anthracene and its derivatives with alkenylazaarenes

Nature Communications, Год журнала: 2024, Номер 15(1)

Опубликована: Май 29, 2024

Abstract Photocatalysis through energy transfer has been investigated for the facilitation of [4 + 2] cycloaddition reactions. However, high reactivity radical species poses a challenging obstacle to achieving enantiocontrol with chiral catalysts, as no enantioselective examples have reported thus far. Here, we present development catalytic asymmetric dearomative photocycloaddition involving anthracene and its derivatives alkenylazaarenes. This accomplishment is achieved by utilizing cooperative photosensitizer Brønsted acid catalysis platform. Importantly, this process enables activation substrates from triplet DPZ, thereby initiating precise stereoselective sequential transformation. The significance our work highlighted synthesis diverse range pharmaceutical valuable cycloadducts incorporating attractive azaarenes, all obtained yields, ees, drs. broad substrate scope further underscored successful construction all-carbon quaternary stereocenters adjacent stereocenters.

Язык: Английский

---

Benzophenothiazine/Boronic Acid Cooperative Photocatalysis Enables the Synthesis of γ-Lactones via the [3 + 2] Cycloaddition of α,β-Unsaturated Carboxylic Acids with Olefins

ACS Catalysis, Год журнала: 2025, Номер unknown, С. 4975 - 4983

Опубликована: Март 10, 2025

Язык: Английский

---

Photo‐Induced Ruthenium‐Catalyzed C−H Benzylations and Allylations at Room Temperature

Chemistry - A European Journal, Год журнала: 2021, Номер 27(65), С. 16237 - 16241

Опубликована: Авг. 26, 2021

The ruthenium-catalyzed synthesis of diarylmethane compounds was realized under exceedingly mild photoredox conditions without the use exogenous photocatalysts. versatility and robustness C-H benzylation reflected by an ample scope, including multifold functionalizations, as well transformable pyrazoles, imidates sensitive nucleosides. Mechanistic studies were indicative a photoactive cyclometalated ruthenium complex, which also enabled versatile allylations.

Язык: Английский

---

Asymmetric Photochemical [2 + 2]-Cycloaddition of Acyclic Vinylpyridines through Ternary Complex Formation and an Uncontrolled Sensitization Mechanism

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(43), С. 20109 - 20117

Опубликована: Окт. 20, 2022

Stereochemical control of photochemical reactions that occur via triplet energy transfer remains a challenge. Suppressing off-catalyst stereorandom reactivity is difficult for highly reactive open-shell intermediates. Strategies suppressing racemate-producing, pathways have long focused on formation ground state, substrate-catalyst chiral complexes are primed photocatalyst in contrast to their counterparts. Herein, we describe strategy where both catalyst-associated vinylpyridine and nonassociated, free substrate can be sensitized by an Ir(III) photocatalyst, yet high levels diastereo- enantioselectivity [2 + 2] photocycloaddition achieved through preferred, organized transition state. This mechanistic paradigm distinct from, complementary current approaches achieving stereocontrol transformations.

Язык: Английский

---