Visible‐Light Photocatalysis: Does It Make a Difference in Organic Synthesis?

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(32), С. 10034 - 10072

Опубликована: Фев. 21, 2018

Visible-light photocatalysis has evolved over the last decade into a widely used method in organic synthesis. Photocatalytic variants have been reported for many important transformations, such as cross-coupling reactions, α-amino functionalizations, cycloadditions, ATRA or fluorinations. To help chemists select photocatalytic methods their synthesis, we compare this Review classical and procedures selected classes of reactions highlight advantages limitations. In cases, proceed under milder reaction conditions, typically at room temperature, stoichiometric reagents are replaced by simple oxidants reductants, air, oxygen, amines. Does visible-light make difference synthesis? The prospect shuttling electrons back forth to substrates intermediates selectively transfer energy through visible-light-absorbing photocatalyst holds promise improve current radical chemistry open up new avenues accessing reactive species hitherto unknown, especially merging with organo- metal catalysis.

Язык: Английский

---

New Strategies for the Transition-Metal Catalyzed Synthesis of Aliphatic Amines

Chemical Reviews, Год журнала: 2020, Номер 120(5), С. 2613 - 2692

Опубликована: Фев. 17, 2020

Transition-metal catalyzed reactions that are able to construct complex aliphatic amines from simple, readily available feedstocks have become a cornerstone of modern synthetic organic chemistry. In light the ever-increasing importance across range chemical sciences, this review aims provide concise overview transition-metal approaches alkylamine synthesis and their functionalization. Selected examples amine bond forming include: (a) hydroamination hydroaminoalkylation, (b) C(sp3)–H functionalization, (c) visible-light-mediated photoredox catalysis.

Язык: Английский

---

New Redox Strategies in Organic Synthesis by Means of Electrochemistry and Photochemistry

ACS Central Science, Год журнала: 2020, Номер 6(8), С. 1317 - 1340

Опубликована: Июль 16, 2020

As the breadth of radical chemistry grows, new means to promote and regulate single-electron redox activities play increasingly important roles in driving modern synthetic innovation. In this regard, photochemistry electrochemistry-both considered as niche fields for decades-have seen an explosive renewal interest recent years gradually have become a cornerstone organic chemistry. Outlook article, we examine current state-of-the-art areas electrochemistry photochemistry, well nascent area electrophotochemistry. These techniques employ external stimuli activate molecules imbue privileged control reaction progress selectivity that is challenging traditional chemical methods. Thus, they provide alternative entries known reactive intermediates enable distinct strategies were previously unimaginable. Of many hallmarks, electro- are often classified "green" technologies, promoting reactions under mild conditions without necessity potent wasteful oxidants reductants. This reviews most growth these with special emphasis on conceptual advances given rise enhanced accessibility tools trade.

Язык: Английский

---

Photochemical Generation of Nitrogen-Centered Amidyl, Hydrazonyl, and Imidyl Radicals: Methodology Developments and Catalytic Applications

ACS Catalysis, Год журнала: 2017, Номер 7(8), С. 4999 - 5022

Опубликована: Июнь 19, 2017

During the past decade, visible light photocatalysis has become a powerful synthetic platform for promoting challenging bond constructions under mild reaction conditions. These photocatalytic systems rely on harnessing energy purposes through generation of reactive but controllable free radical species. Recent progress in area established it as an enabling catalytic strategy and selective nitrogen-centered radicals. The application activation amides, hydrazones, imides represents valuable approach facilitating formation Within span only couple years, significant been made expediting amidyl, hydrazonyl, imidyl radicals from variety precursors. This Perspective highlights recent advances light-mediated these A particular emphasis is placed unique ability accessing elusive manifolds construction diversely functionalized nitrogen-containing motifs nontraditional disconnections contemporary chemistry.

Язык: Английский

---

Photokatalyse mit sichtbarem Licht: Welche Bedeutung hat sie für die organische Synthese?

Angewandte Chemie, Год журнала: 2018, Номер 130(32), С. 10188 - 10228

Опубликована: Фев. 21, 2018

Abstract Die Photokatalyse mit sichtbarem Licht hat sich im letzten Jahrzehnt zu einer breit angewandten Methode in der organischen Synthese entwickelt. Für viele wichtige Reaktionen, wie Kreuzkupplungen, α‐Amino‐Funktionalisierungen, Cycloadditionen, ATRA‐Reaktionen oder Fluorierungen, wurden photokatalytische Varianten berichtet. Um Chemiker bei Auswahl photokatalytischer Methoden für ihre Synthesen unterstützen, vergleichen wir diesem Aufsatz klassische und Verfahren ausgewählte Reaktionsklassen zeigen deren Vorteile Grenzen auf. In vielen Fällen verlaufen die photokatalytischen Reaktionen unter milderen Reaktionsbedingungen, typischerweise Raumtemperatur, stöchiometrische Reagenzien werden durch einfache Oxidanzien Reduktionsmittel Luft, Sauerstoff Amine ersetzt. Beeinflusst organische Synthese? Aussicht, Elektronen Substraten Zwischenprodukten hin‐ herzuschieben Energie selektiv einen sichtbares absorbierenden Photokatalysatoren übertragen, verspricht aktuellen Radikalchemie verbessern neue Wege den Zugang reaktiven, bisher unbekannten Spezies erschließen, insbesondere das Zusammenspiel von Organo‐ Metallkatalyse.

---

Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2017 - 2291

Опубликована: Ноя. 23, 2021

We present here a review of the photochemical and electrochemical applications multi-site proton-coupled electron transfer (MS-PCET) in organic synthesis. MS-PCETs are redox mechanisms which both an proton exchanged together, often concerted elementary step. As such, MS-PCET can function as non-classical mechanism for homolytic bond activation, providing opportunities to generate synthetically useful free radical intermediates directly from wide variety common functional groups. introduction practitioner’s guide reaction design, with emphasis on unique energetic selectivity features that characteristic this class. then chapters oxidative N–H, O–H, S–H, C–H homolysis methods, generation corresponding neutral species. Then, reductive PCET activations involving carbonyl, imine, other X═Y π-systems, heteroarenes, where ketyl, α-amino, heteroarene-derived radicals be generated. Finally, we asymmetric catalysis materials device applications. Within each chapter, subdivide by group undergoing homolysis, thereafter type transformation being promoted. Methods published prior end December 2020 presented.

Язык: Английский

---

Recent advances in radical-based C–N bond formation via photo-/electrochemistry

Chemical Society Reviews, Год журнала: 2018, Номер 47(8), С. 2591 - 2608

Опубликована: Янв. 1, 2018

The employment of nitrogen sources with free N-H bonds for amination is considered to be most straightforward and desirable, especially when the C-N are prepared from non-functionalized carbon sources, such as C-H C-C double/triple bonds, since this obviates needs pre-installation reactive groups in starting materials leads a high atom step economy. Recently, radical chemistry has been resuscitated owing its great value organic synthesis, notable advances have made direct use radical-based bond formation photo-/electrotechniques. Apart well-studied N-radical species addition pathway, radical-mediated aminations also proceed through N-atom nucleophilic addition, C-/N-radical cross-coupling, hydrogen-atom transfer (HAT) process. This review highlights recent area emphasis on related reaction mechanisms.

Язык: Английский

---

Photocatalytic Late-Stage C–H Functionalization

Chemical Reviews, Год журнала: 2023, Номер 123(8), С. 4237 - 4352

Опубликована: Янв. 24, 2023

The emergence of modern photocatalysis, characterized by mildness and selectivity, has significantly spurred innovative late-stage C–H functionalization approaches that make use low energy photons as a controllable source. Compared to traditional strategies, photocatalysis paves the way toward complementary and/or previously unattainable regio- chemoselectivities. Merging compelling benefits with workflow offers potentially unmatched arsenal tackle drug development campaigns beyond. This Review highlights photocatalytic strategies small-molecule drugs, agrochemicals, natural products, classified according targeted bond newly formed one. Emphasis is devoted identifying, describing, comparing main mechanistic scenarios. draws critical comparison between established ionic chemistry photocatalyzed radical-based manifolds. aims establish current state-of-the-art illustrate key unsolved challenges be addressed in future. authors aim introduce general readership functionalization, specialist practitioners evaluation methodologies, potential for improvement, future uncharted directions.

Язык: Английский

---

A Visible‐Light‐Driven Iminyl Radical‐Mediated C−C Single Bond Cleavage/Radical Addition Cascade of Oxime Esters

Angewandte Chemie International Edition, Год журнала: 2017, Номер 57(3), С. 738 - 743

Опубликована: Дек. 7, 2017

Abstract A room‐temperature, visible‐light‐driven N‐centered iminyl radical‐mediated and redox‐neutral C−C single bond cleavage/radical addition cascade reaction of oxime esters unsaturated systems has been accomplished. The strategy tolerates a wide range O‐acyl oximes systems, such as alkenes, silyl enol ethers, alkynes, isonitrile, enabling highly selective formation various chemical bonds. This method thus provides an efficient approach to diversely substituted cyano‐containing ketones, carbocycles, heterocycles.

Язык: Английский

---

Photocatalysis in the Life Science Industry

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2907 - 2980

Опубликована: Сен. 24, 2021

In the pursuit of new pharmaceuticals and agrochemicals, chemists in life science industry require access to mild robust synthetic methodologies systematically modify chemical structures, explore novel space, enable efficient synthesis. this context, photocatalysis has emerged as a powerful technology for synthesis complex often highly functionalized molecules. This Review aims summarize published contributions field from industry, including research industrial-academic partnerships. An overview developed strategic applications synthesis, peptide functionalization, isotope labeling, both DNA-encoded traditional library is provided, along with summary state-of-the-art photoreactor effective upscaling photocatalytic reactions.

Язык: Английский

---