Electrochemical strategies for C–H functionalization and C–N bond formation

Chemical Society Reviews, Год журнала: 2018, Номер 47(15), С. 5786 - 5865

Опубликована: Янв. 1, 2018

This review provides an overview of the use electrochemistry as appealing platform for expediting carbon–hydrogen functionalization and carbon–nitrogen bond formation.

Язык: Английский

---

First-Row Transition Metal (De)Hydrogenation Catalysis Based On Functional Pincer Ligands

Chemical Reviews, Год журнала: 2018, Номер 119(4), С. 2681 - 2751

Опубликована: Дек. 31, 2018

The use of 3d metals in de/hydrogenation catalysis has emerged as a competitive field with respect to "traditional" precious metal catalyzed transformations. introduction functional pincer ligands that can store protons and/or electrons expressed by metal-ligand cooperativity and ligand redox-activity strongly stimulated this development conceptual starting point for rational catalyst design. This review aims at providing comprehensive picture the utilization first-row transition hydrogenation dehydrogenation related synthetic concepts relying on these such hydrogen borrowing methodology. Particular emphasis is put implementation relevance cooperating redox-active within mechanistic scenarios.

Язык: Английский

---

Cross-Coupling and Related Reactions: Connecting Past Success to the Development of New Reactions for the Future

Organometallics, Год журнала: 2018, Номер 38(1), С. 3 - 35

Опубликована: Ноя. 27, 2018

Cross-coupling reactions, which were discovered almost 50 years ago, are widely used in both industry and academia. Even though cross-coupling reactions now represent mature technology, there is still a significant amount of research this area that aims to improve the scope these develop more efficient catalysts, make practical. In tutorial, brief background provided, then major advances over last 20 described. These include development improved ligands precatalysts for extension much wider range electrophiles. For example, common with sp3-hybridized electrophiles as well ester, amide, ether, aziridine substrates. many modern substrates, traditional palladium-based catalysts less than systems based on first-row transition metals such nickel. Conventional have also inspired related cross-electrophile decarboxylative couplings metallaphotoredox chemistry. The new probably at same stage 30 tutorial highlights how strategies may be applicable making

Язык: Английский

---

N‐(Acyloxy)phthalimides as Redox‐Active Esters in Cross‐Coupling Reactions

Advanced Synthesis & Catalysis, Год журнала: 2018, Номер 360(9), С. 1735 - 1753

Опубликована: Фев. 7, 2018

Abstract Recent years have witnessed a resurgence of novel, efficient and practical protocols for radical‐mediated cross‐coupling reactions involving N ‐(acyloxy)phthalimides (NHPI esters) as redox‐active esters. After the initial discovery properties NHPI esters, exciting examples SET‐based under thermal or photolytic conditions leading to diverse C–X (X=C, B, Si, Se, S) bonds been published. The operational simplicity broad applicability exhibited in ester‐based cross‐couplings bode well their widespread adoption. review presented herein covers all recent developments field ester (RAE)‐based since discovery. Depending on employed categorized into photoinduced non‐photoinduced with representative insightful mechanistic discussions. magnified image

Язык: Английский

---

Computational Approach to Molecular Catalysis by 3d Transition Metals: Challenges and Opportunities

Chemical Reviews, Год журнала: 2018, Номер 119(4), С. 2453 - 2523

Опубликована: Окт. 30, 2018

Computational chemistry provides a versatile toolbox for studying mechanistic details of catalytic reactions and holds promise to deliver practical strategies enable the rational in silico catalyst design. The reactivity nontrivial electronic structure effects, common systems based on 3d transition metals, introduce additional complexity that may represent particular challenge standard computational strategies. In this review, we discuss challenges capabilities modern methods reaction mechanisms promoted by metal molecular catalysts. Particular focus will be placed ways addressing multiconfigurational problem calculations role expert bias utilization available methods. development density functionals designed address metals is also discussed. Special emphasis account solvation effects multicomponent nature systems. This followed an overview recent studies processes catalysts metals. Cases involve noninnocent ligands, systems, metal-ligand metal-metal cooperativity, as well modeling complex such metal-organic frameworks are presented. Conventionally, heavily dependent chemical intuition input researcher. Recent developments advanced automated path analysis hold eliminating human-bias from catalysis studies. A brief these approaches presented final section review. paper closed with general concluding remarks.

Язык: Английский

---

Well-Defined Palladium(II)–NHC Precatalysts for Cross-Coupling Reactions of Amides and Esters by Selective N–C/O–C Cleavage

Accounts of Chemical Research, Год журнала: 2018, Номер 51(10), С. 2589 - 2599

Опубликована: Сен. 21, 2018

Transition-metal-catalyzed cross-coupling reactions represent a most powerful tool for the rapid construction of C-C and C-X bonds available to synthetic chemists. Recently, tremendous progress has been made in burgeoning area amides esters enabled by regio- chemoselective acyl (X = N, O) cleavage using well-defined Pd(II)-NHC complexes. The use N-heterocyclic carbenes as ligands palladium-catalyzed cross-couplings permits that were previously impossible palladium or could be achieved only under harsh conditions. These provide an attractive method chemists manipulate traditionally inert amide ester with broad generality inherent catalysis. Research stable electrophiles can broadly categorized type electrophile undergoing cross-coupling. Recent studies have shown transition-metal catalysis represents one straightforward wide-ranging ways manipulating classically into generic acyl-metal intermediates systematically exploited new paradigm organic synthesis. key achieving high chemoselectivity process is control amidic resonance (nN πC═O* conjugation, rotation ca. 15-20 kcal/mol planar amides), enabling oxidative addition N-C bond metal rational predictable manner. This mode extended C(acyl)-O aryl esters, where selective C-O accomplished through match nucleophilic catalysts. two types transition-metal-catalyzed concept chemistry because ubiquity precursors Furthermore, stability provides unprecedented opportunities orthogonal strategies presence other electrophiles. In this Account, we highlight advances taken place past few years field focusing on both (1) stereoelectronic properties complexes critical realize challenging manifold (2) role isomerization barrier broader sense, described here practical approach functionalize common functional groups synthesis establishes access enable nonconventional strategies.

Язык: Английский

---

Photocatalytic Activation of Less Reactive Bonds and Their Functionalization via Hydrogen-Evolution Cross-Couplings

Accounts of Chemical Research, Год журнала: 2018, Номер 51(10), С. 2512 - 2523

Опубликована: Окт. 3, 2018

Cross-coupling reactions have been established as potential tools for manufacture of complex molecular frameworks diversified interests by connecting two simple molecules through the formation a carbon-carbon (C-C) or carbon-heteroatom (C-X) bond. Conventional cross-couplings are transition metal-catalyzed between electrophiles and nucleophiles. Generally, electrophilic partner is an aryl alkenyl halide, nucleophile organometallic reagent, both obtained from prefunctionalization their corresponding hydrocarbons. During past decade, dehydrogenative carbon-hydrogen (C-H) bonds one C-H bond heteroatom-hydrogen (X-H) bond, which build C-C C-X linkage respectively, emerged attractive strategy in synthetic chemistry. Such straightforward couplings allow use less functionalized reagents, thus reducing number steps to target molecule minimizing waste production. However, such involve stoichiometric amounts sacrificial oxidants peroxides, high-valent metals, iodine(III) oxidants. This leads low atom economy possible generation toxic wastes. Recently, visible light photocatalytic cross-coupling received much attention due utilizing sunlight source energy making process appealing. In this approach, metal complexes, organic dyes, semiconductor quantum dots that absorb employed photocatalysts. Upon irradiation, photocatalyst initiates single electron transfer with substrate(s) generate radical cation anion substrate, undergoes desired reaction interest. case, oxygen utilized oxidant hydrogen peroxide only byproduct. These aspects make greener than reactions. Research efforts our group led development environmentally benign construct different X-H photocatalysis. Our hydrogen-evolution reactions, combines proton reduction cocatalyst create dual catalyst system. The former uses driving force cross-coupling, while latter may capture electrons substrates intermediates reduce protons eliminated reactive scaffolds (C-H/C-H C-H/X-H bonds) into (H2). Thus, without any under mild conditions, system affords products excellent yields equimolar amount H2 sole highly step economical particularly useful species sensitive oxidative conditions. Account highlights findings laboratories on featuring activation functionalization C(sp3)-H adjacent amino groups atoms ethers, aromatic C(sp2)-H bonds, several types bonds. We expect combining holds significant transformations.

Язык: Английский

---

Complexes of Ni(i): a “rare” oxidation state of growing importance

Chemical Society Reviews, Год журнала: 2017, Номер 46(17), С. 5347 - 5399

Опубликована: Янв. 1, 2017

The synthesis and diverse structures, reactivity (small molecule activation catalysis) magnetic properties of Ni(i) complexes are summarized.

Язык: Английский

---

Univariate classification of phosphine ligation state and reactivity in cross-coupling catalysis

Science, Год журнала: 2021, Номер 374(6565), С. 301 - 308

Опубликована: Окт. 15, 2021

Which phosphines squeeze together? Phosphine ligands coordinated to palladium and nickel are essential tools for assembling the backbones of pharmaceutical compounds. For decades, descriptors that characterize spatial bulk have helped guide phosphine optimization. However, these tend apply ideal geometries a single ligand. Newman-Stonebraker et al . introduce descriptor considers how ligand conformation might change in crowded environment. Specifically, they found minimum percentage buried volume accurately predicts when one or two particular will coordinate metal center, frequently key determinant successful catalysis. —JSY

Язык: Английский

---

Mechanistic Aspects of the Palladium‐Catalyzed Suzuki‐Miyaura Cross‐Coupling Reaction

Chemistry - A European Journal, Год журнала: 2021, Номер 27(54), С. 13481 - 13493

Опубликована: Июль 16, 2021

The story of C-C bond formation includes several reactions, and surely Suzuki-Miyaura is among the most outstanding ones. Herein, a brief historical overview insights regarding reaction mechanism provided. In particular, catalytically active species probably main concern, thus preactivation in competition with, or even assumes role rate determining step (rds) overall reaction. Computational chemistry key identifying rds leading to milder conditions on an experimental level by means predictive catalysis.

Язык: Английский

---