Discovery and Elucidation of Counteranion Dependence in Photoredox Catalysis DOI
Elliot P. Farney, Steven J. Chapman, Wesley B. Swords

et al.

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(15), P. 6385 - 6391

Published: March 21, 2019

Over the past decade, there has been a renewed interest in use of transition metal polypyridyl complexes as photoredox catalysts for variety innovative synthetic applications. Many derivatives these are known, and effect ligand modifications on their efficacy subject extensive, systematic investigation. However, influence photocatalyst counteranion received little attention, despite fact that generally cationic nature. Herein, we demonstrate effects exert surprising, dramatic impact rate representative photocatalytic radical cation Diels–Alder reaction. A detailed analysis reveals identity impacts multiple aspects reaction mechanism. Most notably, photocatalysts with more noncoordinating counteranions yield powerful triplet excited state oxidant longer chain length. It is proposed this arises from Coulombic ion-pairing interactions between both catalyst intermediate, respectively. The comparatively slower coordinating can be rescued by using hydrogen-bonding anion binders attenuate deleterious interactions. These results importance variable design optimization transformations suggest novel strategy organic reactions class photocatalysts.

Language: Английский

Mechanistic Studies in Photocatalysis DOI Open Access
Luca Buzzetti, Giacomo E. M. Crisenza, Paolo Melchiorre

et al.

Angewandte Chemie International Edition, Journal Year: 2018, Volume and Issue: 58(12), P. 3730 - 3747

Published: Oct. 19, 2018

Abstract The fast‐moving fields of photoredox and photocatalysis have recently provided fresh opportunities to expand the potential synthetic organic chemistry. Advances in light‐mediated processes mainly been guided so far by empirical findings quest for reaction invention. general perception, however, is that entering a more mature phase where combination experimental mechanistic studies will play dominant role sustaining further innovation. This Review outlines key consider when developing photochemical process, best techniques available acquiring relevant information. discussion use selected case highlight how investigations can be instrumental guiding invention development synthetically useful photocatalytic transformations.

Language: Английский

Citations

760
New Redox Strategies in Organic Synthesis by Means of Electrochemistry and Photochemistry DOI Creative Commons
Jinjian Liu, Lingxiang Lu, Devin Wood

et al.

ACS Central Science, Journal Year: 2020, Volume and Issue: 6(8), P. 1317 - 1340

Published: July 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.

Language: Английский

Citations

375
Photochemical and Electrochemical Applications of Proton-Coupled Electron Transfer in Organic Synthesis DOI Creative Commons
Philip R. D. Murray, James H. Cox, Nicholas D. Chiappini

et al.

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2017 - 2291

Published: Nov. 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.

Language: Английский

Citations

352
Strategic Use of Visible-Light Photoredox Catalysis in Natural Product Synthesis DOI
Spencer P. Pitre, Larry E. Overman

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 1717 - 1751

Published: July 7, 2021

Recent progress in the development of photocatalytic reactions promoted by visible light is leading to a renaissance use photochemistry construction structurally elaborate organic molecules. Because rich functionality found natural products, studies product total synthesis provide useful insights into functional group compatibility these new methods as well their impact on synthetic strategy. In this review, we examine syntheses published through end 2020 that employ visible-light photoredox catalytic step. To assist someone interested employing steps discussed, review organized largely nature bond formed

Language: Английский

Citations

325
Chiral phosphoric acid-catalyzed asymmetric dearomatization reactions DOI

Zilei Xia,

Qing‐Feng Xu‐Xu, Chao Zheng

et al.

Chemical Society Reviews, Journal Year: 2019, Volume and Issue: 49(1), P. 286 - 300

Published: Dec. 12, 2019

We summarize in this review the recent development of chiral phosphoric acid (CPA)-catalyzed asymmetric dearomatization reactions.

Language: Английский

Citations

315
Catalytic asymmetric dearomatization (CADA) reaction-enabled total synthesis of indole-based natural products DOI
Chao Zheng, Shu‐Li You

Natural Product Reports, Journal Year: 2019, Volume and Issue: 36(11), P. 1589 - 1605

Published: Jan. 1, 2019

The recent enantioselective total syntheses of natural products enabled by catalytic asymmetric dearomatization reactions indole derivatives are presented.

Language: Английский

Citations

310
Visible light-mediated chemistry of indoles and related heterocycles DOI
Alexey А. Festa, Leonid G. Voskressensky, Erik V. Van der Eycken

et al.

Chemical Society Reviews, Journal Year: 2019, Volume and Issue: 48(16), P. 4401 - 4423

Published: Jan. 1, 2019

The impact of visible light-promoted chemistry on the functionalization indoles and related heterocycles is reviewed.

Language: Английский

Citations

261
Radicals in natural product synthesis DOI
Kevin Romero, Matthew S. Galliher, Derek A. Pratt

et al.

Chemical Society Reviews, Journal Year: 2018, Volume and Issue: 47(21), P. 7851 - 7866

Published: Jan. 1, 2018

Free radical intermediates have intrigued chemists since their discovery, and an ever-increasing appreciation for unique reactivity has resulted in the widespread utilization of these species natural product synthesis.

Language: Английский

Citations

256
Enantioselective Radical Reactions Using Chiral Catalysts DOI
Shovan Mondal, Frédéric Dumur, Didier Gigmès

et al.

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(6), P. 5842 - 5976

Published: Jan. 24, 2022

Benefiting from the impressive increase in fundamental knowledge, last 20 years have shown a continuous burst of new ideas and consequently plethora catalytic methods for enantioselective radical reactions. This review aims to provide complete survey progress achieved over this latter period. The first part focuses on use chiral organocatalysts, these include catalysts covalently linked substrate those that interact with by weaker interactions like hydrogen bonds. second is devoted transition-metal redox catalysis which organized according increasing atomic number first-row transition metals (Ti, Cr, Fe, Mn, Co, Ni, Cu). Bioinspired manganese- iron-mediated hydroxylations oxidations are also discussed. A specific section dedicated reactivity Ru, Rh, Ir complexes as Lewis acids special focus at metal. Absorption photons result different events such energy transfer, single-electron hydrogen-atom transfer facilitating formation radicals. Organocatalysis has been successfully combined photocatalysts, opened pathways enlarging precursors available. merger photocatalysis organo- or metalla-photocatalysis brought novelty allowed discovery large original transformations. enzyme-catalyzed reactions involving intermediates largely benefit visible-light irradiation included review. provides comprehensive inventory goal detailing reaction mechanisms involved transformations any nonspecialist could find their own creativity invent yet unknown applications.

Language: Английский

Citations

253
Nitrogen-Centered Radicals in Functionalization of sp2 Systems: Generation, Reactivity, and Applications in Synthesis DOI Creative Commons
Cassie Pratley, Sabine Fenner, John A. Murphy

et al.

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(9), P. 8181 - 8260

Published: March 14, 2022

The chemistry of nitrogen-centered radicals (NCRs) has plentiful applications in organic synthesis, and they continue to expand as our understanding these reactive species increases. utility intermediates is demonstrated the recent advances C–H amination (di)amination alkenes. Synthesis previously challenging structures can be achieved by efficient functionalization sp2 moieties without prefunctionalization, allowing for faster more streamlined synthesis. This Review addresses generation, reactivity, application NCRs, including, but not limited to, iminyl, aminyl, amidyl, aminium species. Contributions from early discovery up most examples have been highlighted, covering radical initiation, thermolysis, photolysis, and, recently, photoredox catalysis. Radical-mediated intermolecular (hetero)arenes occur with a variety complex amine precursors, generating aniline derivatives, an important class drug development. Functionalization olefins achievable high anti-Markovnikov regioselectivity allows access difunctionalized when intermediate carbon are trapped. Additionally, reactivity NCRs harnessed rapid construction N-heterocycles such pyrrolidines, phenanthridines, quinoxalines, quinazolinones.

Language: Английский

Citations

240