Bond-Forming and -Breaking Reactions at Sulfur(IV): Sulfoxides, Sulfonium Salts, Sulfur Ylides, and Sulfinate Salts

Chemical Reviews, Год журнала: 2019, Номер 119(14), С. 8701 - 8780

Опубликована: Июнь 25, 2019

Organosulfur compounds have long played a vital role in organic chemistry and the development of novel chemical structures architectures. Prominent among these organosulfur are those involving sulfur(IV) center, which been subject countless investigations over more than hundred years. In addition to list textbook sulfur-based reactions, there has sustained interest organosulfur(IV) recent Of particular within is ease with synthetic chemist can effect wide range transformations through either bond formation or cleavage at sulfur. This review aims cover developments past decade molecules provide insight into both reactions critically rely on this versatile element diverse scaffolds that thereby be synthesized.

Язык: Английский

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Transition‐Metal‐Catalyzed Carboxylation Reactions with Carbon Dioxide

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(49), С. 15948 - 15982

Опубликована: Май 3, 2018

Driven by the inherent synthetic potential of CO2 as an abundant, inexpensive and renewable C1 chemical feedstock, recent years have witnessed renewed interest in devising catalytic fixations into organic matter. Although formation C-C bonds via fixation remained rather limited for a long period time, close look literature data indicates that carboxylation reactions entered new era exponential growth, evolving mature discipline allows streamlining synthesis carboxylic acids, building blocks utmost relevance industrial endeavors. These strategies generally proven broadly applicability convenient to perform. However, substantial challenges still need be addressed reinforcing cover metal-catalyzed area conceptual concise manner, delineating underlying principles are slowly emerging this vibrant expertise.

Язык: Английский

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Visible light-driven organic photochemical synthesis in China

Science China Chemistry, Год журнала: 2018, Номер 62(1), С. 24 - 57

Опубликована: Дек. 21, 2018

Язык: Английский

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Photons or Electrons? A Critical Comparison of Electrochemistry and Photoredox Catalysis for Organic Synthesis

Chemical Reviews, Год журнала: 2021, Номер 122(2), С. 2487 - 2649

Опубликована: Ноя. 9, 2021

Redox processes are at the heart of synthetic methods that rely on either electrochemistry or photoredox catalysis, but how do and catalysis compare? Both approaches provide access to high energy intermediates (e.g., radicals) enable bond formations not constrained by rules ionic 2 electron (e) mechanisms. Instead, they 1e mechanisms capable bypassing electronic steric limitations protecting group requirements, thus enabling chemists disconnect molecules in new different ways. However, while providing similar intermediates, differ several physical chemistry principles. Understanding those differences can be key designing transformations forging disconnections. This review aims highlight these similarities between comparing their underlying principles describing impact electrochemical photochemical methods.

Язык: Английский

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sp³ C–H Arylation and Alkylation Enabled by the Synergy of Triplet Excited Ketones and Nickel Catalysts

Journal of the American Chemical Society, Год журнала: 2018, Номер 140(38), С. 12200 - 12209

Опубликована: Сен. 5, 2018

Triplet ketone sensitizers are of central importance within the realm photochemical transformations. Although radical-type character triplet excited states diaryl ketones suggests viability for triggering hydrogen-atom transfer (HAT) and single-electron (SET) processes, among others, their use as multifaceted catalysts in C–C bond-formation via sp3 C–H functionalization alkane feedstocks still remains rather unexplored. Herein, we unlock a modular platform forging C(sp3)–C(sp2) C(sp3)–C(sp3) linkages from abundant bonds functional handles using synergy between nickel simple, cheap ketones. This method is distinguished by its wide scope that obtained starting precursors, thus complementing existing inner-sphere protocols or recent photoredox scenarios based on iridium polypyridyl complexes. Additionally, such provides new strategy streamlining synthesis complex molecules with high levels predictable site-selectivity preparative utility. Mechanistic experiments suggest abstraction occurs HAT state. We believe this study will contribute to more systematic utilization metallaphotoredox scenarios.

Язык: Английский

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Radical Carboxylative Cyclizations and Carboxylations with CO₂

Accounts of Chemical Research, Год журнала: 2021, Номер 54(10), С. 2518 - 2531

Опубликована: Май 6, 2021

ConspectusCarbon dioxide (CO2) is not only a greenhouse gas and common waste product but also an inexpensive, readily available, renewable carbon resource. It important one-carbon (C1) building block in organic synthesis for the construction of valuable compounds. However, its utilization challenging owing to thermodynamic stability kinetic inertness. Although significant progress has been achieved, many limitations remain this field with regard substrate scope, reaction system, activation strategies.Since 2015, our group focused on CO2 synthesis. We are interested vast possibilities radical chemistry, although high reactivity radicals presents challenges controlling selectivity. hope develop highly useful transformations involving by achieving balance selectivity under mild conditions. Over past 6 years, we along other experts have disclosed radical-type carboxylative cyclizations carboxylations using CO2.We initiated research realizing Cu-catalyzed oxytrifluoromethylation allylamines heteroaryl methylamines generate 2-oxazolidones various precursors. Apart from Cu catalysis, visible-light photoredox catalysis powerful method achieve efficient cyclization. In these cases, single-electron-oxidation-promoted C–O bond formation between benzylic carbamates key step.Since carboxylic acids exist widely natural products bioactive drugs serve as bulk chemicals industry, realized further visible-light-promoted construct such chemicals. achieved selective umpolung imines, enamides, tetraalkylammonium salts, oxime esters successive single-electron-transfer (SSET) reduction. Using strategy, dearomative arylcarboxylation indoles CO2. addition incorporation 1 equiv per substrate, recently developed photoredox-catalyzed dicarboxylation alkenes, allenes, (hetero)arenes via SSET reduction, which allows two molecules into compounds diacids polymer precursors.In two-electron CO2, sought new strategies realize single-electron Inspired hypothetical electron-transfer mechanism iron–sulfur proteins, visible-light-driven thiocarboxylation alkenes catalytic iron salts promoters. The in-situ-generated Fe/S complexes likely able reduce anion, could react give stabilized radical. Moreover, charge-transfer complex (CTC) thiolate acrylate/styrene hydrocarboxylation generation or alkene anion. On basis novel CTC, organocatalytic Hantzsch ester effective reductant.

Язык: Английский

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Visible‐Light‐Mediated Metal‐Free Difunctionalization of Alkenes with CO₂ and Silanes or C(sp³)−H Alkanes

Angewandte Chemie International Edition, Год журнала: 2018, Номер 57(52), С. 17220 - 17224

Опубликована: Ноя. 9, 2018

Catalytic alkene difunctionalization via Si-H and C-H activations represents an ideal atom- step-economic pathway for quick assembly of molecular complexity. We herein developed a visible-light-promoted metal-free alkenes using abundant CO2 readily available C(sp3 )-H bonds as feedstocks. Through the merger photoredox hydrogen-atom-transfer catalysis, variety value-added compounds, such β-silacarboxylic acids bearing γ-heteroatom (e.g., N, O, S) could be directly accessed from simple in redox-neutral fashion.

Язык: Английский

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Photocarboxylation of Benzylic C–H Bonds

Journal of the American Chemical Society, Год журнала: 2019, Номер 141(29), С. 11393 - 11397

Опубликована: Июль 8, 2019

The carboxylation of sp3-hybridized C–H bonds with CO2 is a challenging transformation. Herein, we report visible-light-mediated benzylic into 2-arylpropionic acids under metal-free conditions. Photo-oxidized triisopropylsilanethiol was used as the hydrogen atom transfer catalyst to afford radical that accepts an electron from reduced form 2,3,4,6-tetra(9H-carbazol-9-yl)-5-(1-phenylethyl)benzonitrile generated in situ. resulting carbanion reacts generate corresponding carboxylic acid after protonation. reaction proceeded without addition any sacrificial donor, acceptor or stoichiometric additives. Moderate good yields desired products were obtained broad substrate scope. Several drugs successfully synthesized using novel strategy.

Язык: Английский

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New Horizons of Photocatalytic Fluoromethylative Difunctionalization of Alkenes

Chem, Год журнала: 2017, Номер 4(3), С. 409 - 437

Опубликована: Дек. 21, 2017

Язык: Английский

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Reductive radical-polar crossover: traditional electrophiles in modern radical reactions

Chemical Science, Год журнала: 2019, Номер 10(36), С. 8285 - 8291

Опубликована: Янв. 1, 2019

The concept of reductive radical-polar crossover (RRPCO) reactions has recently emerged as a valuable and powerful tool to overcome limitations both radical traditional polar chemistry.

Язык: Английский

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