C–H Activation: Toward Sustainability and Applications

ACS Central Science, Год журнала: 2021, Номер 7(2), С. 245 - 261

Опубликована: Фев. 2, 2021

Since the definition of "12 Principles Green Chemistry" more than 20 years ago, chemists have become increasingly mindful need to conserve natural resources and protect environment through judicious choice synthetic routes materials. The direct activation functionalization C–H bonds, bypassing intermediate functional group installation is, in abstracto, step atom economic, but numerous factors still hinder sustainability large-scale applications. In this Outlook, we highlight research areas seeking overcome challenges activation: pursuit abundant metal catalysts, avoidance static directing groups, replacement oxidants, introduction bioderived solvents. We close by examining progress made subfield aryl borylation from its origins, highly efficient precious Ir-based systems, emerging 3d catalysts. future growth field will depend on industrial uptake, thus urge researchers strive toward sustainable activation.

Язык: Английский

---

Exploiting hexafluoroisopropanol (HFIP) in Lewis and Brønsted acid-catalyzed reactions

Chemical Communications, Год журнала: 2020, Номер 56(78), С. 11548 - 11564

Опубликована: Янв. 1, 2020

Hexafluoroisopropanol (HFIP) is a solvent with unique properties that has recently gained attention for promoting wide range of challenging chemical reactions. It was initially believed HFIP almost exclusively involved in the stabilization cationic intermediates, owing to its high polarity and low nucleophilicity. However, many cases, mechanism action appears be more complex. Recent findings reveal Lewis Brønsted acid-catalyzed transformations conducted additionally involve cooperation between catalyst hydrogen-bond clusters, akin Lewis- or acid-assisted-Brønsted acid catalysis. This feature article showcases remarkable versatility reactions, an emphasis on examples yielding mechanistic insight.

Язык: Английский

---

Hexafluoroisopropanol: the magical solvent for Pd-catalyzed C–H activation

Chemical Science, Год журнала: 2021, Номер 12(11), С. 3857 - 3870

Опубликована: Янв. 1, 2021

Among numerous solvents available for chemical transformations, 1,1,1,3,3,3-hexafluoro-2-propanol (popularly known as HFIP) has attracted enough attention of the scientific community in recent years.

Язык: Английский

---

Replacement of Less-Preferred Dipolar Aprotic and Ethereal Solvents in Synthetic Organic Chemistry with More Sustainable Alternatives

Chemical Reviews, Год журнала: 2022, Номер 122(6), С. 6749 - 6794

Опубликована: Фев. 24, 2022

Dipolar aprotic and ethereal solvents comprise just over 40% of all organic utilized in synthetic organic, medicinal, process chemistry. Unfortunately, many the common "go-to" are considered to be "less-preferable" for a number environmental, health, safety (EHS) reasons such as toxicity, mutagenicity, carcinogenicity, or practical handling flammability volatility. Recent legislative changes have initiated implementation restrictions on use commonly employed dipolar dimethylformamide (DMF) N-methyl-2-pyrrolidinone (NMP), ethers 1,4-dioxane. Thus, with growing legislative, EHS, societal pressures, need identify implement alternative that greener, safer, more sustainable has never been greater. Within this review, ubiquitous nature is discussed respect physicochemical properties made them so appealing chemists. An overview current being imposed discussed. A variety alternative, garnered attention past decade then examined, case studies examples where less-preferable successfully replaced safer highlighted. Finally, general guidance solvent selection replacement included Supporting Information review.

Язык: Английский

---

Photoinduced Regiodivergent and Enantioselective Cross-Coupling of Glycine Derivatives with Hydrocarbon Feedstocks

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 2, 2025

Regiodivergent asymmetric synthesis represents a transformative strategy for the efficient generation of structurally diverse chiral products from single set starting materials, significantly enriching their enantiomeric composition. However, design radical-mediated regiodivergent and enantioselective reactions that can accommodate wide range functional groups substrates has posed significant challenges. The obstacles primarily lie in switching regioselectivity achieving high enantiodiscrimination, especially when dealing with high-energy intermediates. To address these issues, we have developed new catalytic system integrates photoinduced hydrogen atom transfer (HAT) copper catalysis, involving fine-tuning ligands, additives, other reaction parameters. facilitates cross-couplings between N-aryl glycine ester/amide derivatives abundant hydrocarbon feedstocks through strong C(sp3)–H bond activation. This approach allows controlled stereoselective formation C(sp3)–C(sp3) C(sp3)–N bonds, yielding rich variety C- or N-alkylated esters amides commendable yields (up to 92% yield), exclusive regioselectivities (typically >20:1 rr), enantioselectivities 96% ee). Our methodology not only provides promising avenue incorporation alkyl functionalities onto specific sites biologically molecules but also offers practical while simultaneously induction within photochemical reactions.

Язык: Английский

---

Chlorinated Solvents: Their Advantages, Disadvantages, and Alternatives in Organic and Medicinal Chemistry

Chemical Reviews, Год журнала: 2020, Номер 121(3), С. 1582 - 1622

Опубликована: Дек. 22, 2020

Chlorinated solvents were once, and in many places are still, ubiquitous chemistry laboratories. This review explores the properties that led to such widespread use, why there is now an increasing drive minimize usage, what alternatives currently available.

Язык: Английский

---

Mechanochemical Solvent‐Free Catalytic C−H Methylation

Angewandte Chemie International Edition, Год журнала: 2020, Номер 60(12), С. 6660 - 6666

Опубликована: Окт. 8, 2020

The mechanochemical, solvent-free, highly regioselective, rhodium-catalyzed C-H methylation of (hetero)arenes is reported. reaction shows excellent functional-group compatibility and demonstrated to work for the late-stage biologically active compounds. method requires no external heating benefits from considerably shorter times than previous solution-based protocols. Additionally, mechanochemical approach shown enable efficient synthesis organometallic complexes that are difficult generate conventionally.

Язык: Английский

---

Unlocking the Friedel-Crafts arylation of primary aliphatic alcohols and epoxides driven by hexafluoroisopropanol

Chem, Год журнала: 2021, Номер 7(12), С. 3425 - 3441

Опубликована: Ноя. 17, 2021

Alcohols and epoxides are arguably ideal electrophiles for the Friedel-Crafts alkylation, since they widely available, require no pre-activation, produce stoichiometric waste beyond water. However, neither primary aliphatic alcohols nor most classes of terminal compatible with existing intermolecular methodologies, sequential reactions starting from consequently remain underexplored. Here, we report that these limitations easily overcome using Brønsted acid catalysis in hexafluoroisopropanol (HFIP) as a solvent. Electron-poor aromatic undergo stereospecific arylation to give an alcohol which, depending on reaction conditions, can partake second nucleophilic substitution different arene one pot. Phenyl ethanols react through phenonium intermediate, whereas simple participate rare SN2 process, delivering linear products exclusively. This work provides alternative metal-catalyzed cross-couplings accessing important scaffolds, widening range applications reaction.

Язык: Английский

---

Difunctionalization Processes Enabled by Hexafluoroisopropanol

ACS Organic & Inorganic Au, Год журнала: 2024, Номер 4(3), С. 287 - 300

Опубликована: Март 4, 2024

In the past 5 years, hexafluoroisopropanol (HFIP) has been used as a unique solvent or additive to enable challenging transformations through substrate activation and stabilization of reactive intermediates. this Review, we aim at describing difunctionalization processes which were unlocked when HFIP was involved. Specifically, focus on cyclizations additions alkenes, alkynes, epoxides, carbonyls that introduce wide range functional groups interest.

Язык: Английский

---

Hexafluoroisopropanol Promoted Ring‐Opening‐Cyclization of Donor–Acceptor Cyclopropanes with Primary Amines

European Journal of Organic Chemistry, Год журнала: 2024, Номер 27(22)

Опубликована: Март 19, 2024

Abstract We reveal here a catalyst‐free, ring‐opening‐cyclization of donor‐acceptor cyclopropanes with primary amines to synthesize functionalized dihydropyrroles. This protocol avoids inert conditions and solvents promoted by hexafluoroisopropanol (HFIP). The reaction is quite general aryl, alkyl, alicyclic amines. A good number bearing keto groups reacted excellently produce the desired products. Further, we complemented this method Meldrum's acid‐derived for synthesizing γ‐lactams. have demonstrated post‐synthetic applications products gram‐scale synthesis highlight adaptability synthetic protocol.

Язык: Английский

---