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

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

---

Transition Metal-Catalyzed Tandem Reactions of Ynamides for Divergent N-Heterocycle Synthesis

Accounts of Chemical Research, Journal Year: 2020, Volume and Issue: 53(9), P. 2003 - 2019

Published: Sept. 1, 2020

ConspectusYnamides are electron-rich heteroatom-substituted alkynes with a C-C triple bond directly attached to the amide group. Importantly, this group is able impose an electronic bias, thus resulting in highly regioselective attack of polarized alkyne by large variety nucleophiles. Over past two decades, catalytic reactions ynamides have experienced dramatic developments, especially those catalyzed transition metals. As result, been widely applied rapid and efficient assembly versatile structurally complex N-containing molecules, atom-economic stereoselective way.On basis newly developed ynamide preparations new transformations, we first oxidation-initiated tandem such as zinc-catalyzed oxidation/C-H functionalization copper-catalyzed oxidation/carbene metathesis, leading divergent synthesis isoquinolones, β-carbolines, pyrrolo[3,4-c]quinolin-1-ones. protocol represents non-noble-metal-catalyzed intermolecular oxidation N-oxide type oxidants, related overoxidation could be dramatically inhibited non-noble-metal catalysis. Then, achieved gold-catalyzed amination-initiated via α-imino gold carbenes for construction various 2-aminoindoles, 3-amino-β-carbolines, 2-aminopyrroles, where types nitrene transfer reagents (benzyl azides isoxazoles) were discovered. In particular, use isoxazoles generation metal has also elegantly exploited Hashmi, Liu, many other groups, providing ready access wide range functionalized N-heterocycles. Moreover, revealed that donor/donor copper generated diyne cyclization under mild conditions. These novel undergo asymmetric C-H insertion, cyclopropanation, formal [3 + 2] cycloaddition produce diverse chiral polycyclic pyrroles good excellent enantioselectivities. Thus, strategy may open avenues reaction ynamides, which remain largely unexplored deserve more attention. Meanwhile, accomplished practical medium-sized lactams yttrium-catalyzed cascade allyl alcohol-tethered combination radical chemistry based on visible-light photoredox catalysis useful 2-benzhydrylindoles 3-benzhydrylisoquinolines.In Account, describe panoramic picture our recent contributions since 2015 development application organic metal-catalyzed focusing tetrafunctionalization ynamides. studies provide not only attractive methods valuable N-heterocycles but some insights into exploration carbene chemistry.

Language: Английский

---

Radical-mediated rearrangements: past, present, and future

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(20), P. 11577 - 11613

Published: Jan. 1, 2021

This Review summarizes the past to present achievements in radical-mediated rearrangements, and brings up prospects that may inspire colleagues develop more useful synthetic tools based on radical rearrangements.

Language: Английский

---

Brønsted acid-mediated reactions of ynamides

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(24), P. 8897 - 8909

Published: Jan. 1, 2020

This review summarizes the latest trends and developments of Brønsted acid-mediated reactions ynamides, including cycloaddition, cyclization so on.

Language: Английский

---

Asymmetric synthesis with ynamides: unique reaction control, chemical diversity and applications

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(23), P. 8543 - 8583

Published: Jan. 1, 2020

The diversity, utility and mechanistic aspects of asymmetric synthesis with ynamides developed during the last decade is discussed.

Language: Английский

---

Desulfonylation via Radical Process: Recent Developments in Organic Synthesis

Chemical Reviews, Journal Year: 2021, Volume and Issue: 121(20), P. 12548 - 12680

Published: Aug. 13, 2021

As the "chemical chameleon", sulfonyl-containing compounds and their variants have been merged with various types of reactions for efficient construction diverse molecular architectures by taking advantage incredible reactive flexibility. Currently, involvement in radical transformations, which sulfonyl group typically acts as a leaving via selective C–S, N–S, O–S, S–S, Se–S bond cleavage/functionalization, has facilitated new formation strategies are complementary to classical two-electron cross-couplings organometallic or ionic intermediates. Considering great influence synthetic potential these novel avenues, we summarize recent advances this rapidly expanding area discussing reaction designs, substrate scopes, mechanistic studies, limitations, outlining state-of-the-art processes involved radical-mediated desulfonylation related transformations. With specific emphasis on applications, believe review will be useful medicinal organic chemists who interested chemistry particular.

Language: Английский

---

Aryl Transfer Strategies Mediated by Photoinduced Electron Transfer

Chemical Reviews, Journal Year: 2021, Volume and Issue: 122(2), P. 2695 - 2751

Published: Oct. 21, 2021

Radical aryl migrations are powerful techniques to forge new bonds in aromatic compounds. The growing popularity of photoredox catalysis has led an influx novel strategies initiate and control migration starting from widely available radical precursors. This review encapsulates progress enabled by photochemical methods─particularly catalysis─since 2015. Special attention is paid descriptions scope, mechanism, synthetic applications each method.

Language: Английский

---

Recent advances in the chemistry of ketyl radicals

Chemical Society Reviews, Journal Year: 2021, Volume and Issue: 50(9), P. 5349 - 5365

Published: Jan. 1, 2021

Ketyl radicals are valuable reactive intermediates for synthesis and used extensively to construct complex, functionalized products from carbonyl substrates. Single electron transfer (SET) reduction of the C[double bond, length as m-dash]O bond aldehydes ketones is classical approach formation ketyl metal reductants archetypal reagents employed. The past decade has, however, witnessed significant advances in generation harnessing radicals. This tutorial review highlights recent, exciting developments chemistry by comparing varied contemporary - example, using photoredox catalysts more approaches use will focus on different strategies radical generation, their creative new synthetic protocols, control enantioselectivity, detailed mechanisms where appropriate.

Language: Английский

---

Recent Progress in Synthetic Applications of Hypervalent Iodine(III) Reagents

Chemical Reviews, Journal Year: 2024, Volume and Issue: unknown

Published: Sept. 13, 2024

Hypervalent iodine(III) compounds have found wide application in modern organic chemistry as environmentally friendly reagents and catalysts. iodine are commonly used synthetically important halogenations, oxidations, aminations, heterocyclizations, various oxidative functionalizations of substrates. Iodonium salts arylating reagents, while iodonium ylides imides excellent carbene nitrene precursors. Various derivatives benziodoxoles, such azidobenziodoxoles, trifluoromethylbenziodoxoles, alkynylbenziodoxoles, alkenylbenziodoxoles group transfer the presence transition metal catalysts, under metal-free conditions, or using photocatalysts photoirradiation conditions. Development hypervalent catalytic systems discovery highly enantioselective reactions chiral represent a particularly recent achievement field chemistry. Chemical transformations promoted by many cases unique cannot be performed any other common, non-iodine-based reagent. This review covers literature published mainly last 7-8 years, between 2016 2024.

Language: Английский

---

A Radical Smiles Rearrangement Promoted by Neutral Eosin Y as a Direct Hydrogen Atom Transfer Photocatalyst

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(26), P. 11357 - 11362

Published: June 16, 2020

A visible-light-mediated radical Smiles rearrangement has been achieved using neutral eosin Y as a direct hydrogen atom transfer (HAT) photocatalyst. Novel N-heterocycles single diastereomers featuring an isothiazolidin-3-one 1,1-dioxide moiety are directly accessed by this method. wide range of functional groups can be incorporated in the products employing diverse aldehydes and N-(hetero)arylsulfonyl propiolamides. The transformation proceeds through cascade visible-light-induced HAT, 1,4-addition, rearrangement, 5-endo-trig cyclization, reverse HAT process. Preliminary biological studies highly functionalized heterocyclic compounds suggest potential anticancer activity with some synthesized compounds.

Language: Английский

---