Progress in organocatalysis with hypervalent iodine catalysts

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(18), P. 8102 - 8139

Published: Jan. 1, 2022

Hypervalent iodine compounds as environmentally friendly and relatively inexpensive reagents have properties similar to transition metals. They are employed alternatives metal catalysts in organic synthesis mild, nontoxic, selective recyclable catalytic reagents. Formation of C-N, C-O, C-S, C-F C-C bonds can be seamlessly accomplished by hypervalent catalysed oxidative functionalisations. The aim this review is highlight recent developments the utilisation iodine(III) iodine(V) a wide range including chiral for stereoselective synthesis. Polymer-, magnetic nanoparticle- framework-supported also described.

Language: Английский

Palladium-Catalyzed Organic Reactions Involving Hypervalent Iodine Reagents

Molecules, Journal Year: 2022, Volume and Issue: 27(12), P. 3900 - 3900

Published: June 17, 2022

The chemistry of polyvalent iodine compounds has piqued the interest researchers due to their role as important and flexible reagents in synthetic organic chemistry, resulting a broad variety useful molecules. These chemicals have potential uses various functionalization procedures non-toxic environmentally friendly properties. As they are also strong electrophiles potent oxidizing agents, use hypervalent palladium-catalyzed transformations received lot attention recent years. Extensive research been conducted on subject C—H bond by Pd catalysis with oxidants. Furthermore, iodine(III) reagent is now often used an arylating agent Pd-catalyzed arylation or Heck-type cross-coupling processes. In this article, advances oxidative reactions employing reviewed detail.

Language: Английский

Non-Palladium-Catalyzed Oxidative Coupling Reactions Using Hypervalent Iodine Reagents

Frontiers in Chemistry, Journal Year: 2022, Volume and Issue: 10

Published: July 1, 2022

Transition metal-catalyzed direct oxidative coupling reactions via C-H bond activation have emerged as a straightforward strategy for the construction of complex molecules in organic synthesis. The transformation bonds into carbon-carbon and carbon-heteroatom renders requirement prefunctionalization starting materials and, therefore, represents more efficient alternative to traditional cross-coupling reactions. key unprecedented progress made this area has been identification an appropriate oxidant that facilitates oxidation provides heteroatom ligands at metal center. In context, hypervalent iodine compounds evolved mainstream reagents particularly because their excellent oxidizing nature, high electrophilicity, versatile reactivity. They are environmentally benign reagents, stable, non-toxic, relatively cheaper than inorganic oxidants. For many years, palladium catalysis dominated these reactions, but eventually, other transition catalysts such gold, copper, platinum, iron, etc. were found be promising alternate facilitating This review article critically summarizes recent developments non-palladium-catalyzed mediated by (III) with significant emphasis on understanding mechanistic aspects detail.

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

Formation of Isolable Dearomatized [4 + 2] Cycloadducts from Benzenes, Naphthalenes, and N-Heterocycles Using 1,2-Dihydro-1,2,4,5-tetrazine-3,6-diones as Arenophiles under Visible Light Irradiation

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(16), P. 9326 - 9333

Published: April 13, 2023

We report that the dearomative [4 + 2] cycloaddition between 1,2-dihydro-1,2,4,5-tetrazine-3,6-diones (TETRADs) and benzenes, naphthalenes, or N-heteroaromatic compounds under visible light irradiation affords corresponding isolable cycloadducts. Several synthetic transformations including transition-metal-catalyzed allylic substitution reactions using isolated cycloadducts at room temperature above were demonstrated. Computational studies revealed retro-cycloaddition of benzene–TETRAD adduct proceeds via an asynchronous concerted mechanism, while benzene–MTAD (MTAD = 4-methyl-1,2,4-triazoline-3,5-dione) a synchronous mechanism.

Language: Английский

Rh(III)-Catalyzed Atroposelective C–H Iodination of 1-Aryl Isoquinolines

ACS Catalysis, Journal Year: 2023, Volume and Issue: 13(8), P. 5127 - 5134

Published: March 30, 2023

The rhodium-catalyzed enantioselective C–H iodination of 1-aryl isoquinolines under mild conditions is disclosed. Direct with N-iodosuccinimide (NIS) catalyzed by chiral CpRh(III) complexes afforded a series axially biaryl iodides in excellent yields and enantioselectivity (up to 99% yield 97% ee). Furthermore, the atroposelective bromination chlorination reactions were also compatible. Notably, could be easily transformed QUINAP-type N,N-type ligands.

Language: Английский

Catalyst-Substrate Helical Character Matching Determines the Enantioselectivity in the Ishihara-Type Iodoarenes Catalyzed Asymmetric Kita-Dearomative Spirolactonization

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(13), P. 7301 - 7312

Published: March 20, 2023

Catalyst design has traditionally focused on rigid structural elements to prevent conformational flexibility. Ishihara's elegant of conformationally flexible C2-symmetric iodoarenes, a new class privileged organocatalysts, for the catalytic asymmetric dearomatization (CADA) naphthols is notable exception. Despite widespread use Ishihara catalysts CADAs, reaction mechanism remains subject debate, and mode induction not been well established. Here, we report an in-depth computational investigation three possible mechanisms in literature. Our results, however, reveal that this best rationalized by fourth called "proton-transfer-coupled-dearomatization (PTCD)", which predicted be strongly favored over other competing pathways. The PTCD consistent with control experiment further validated applying it rationalize enantioselectivities. Oxidation I(I) catalyst active I(III) species induces defined helical chiral environment delicate balance between flexibility rigidity. A match/mismatch effect substrate's shape transition states was observed. match allows adapt its conformation maximize attractive noncovalent interactions, including I(III)···O halogen bond, N-H···O hydrogen π···π stacking, stabilize state. stereochemical model capable rationalizing variation enantioselectivities developed. present study enriches our understanding how achieve high stereoinduction may serve as inspiration future exploration designs.

Language: Английский

Asymmetric Aminative Dearomatization of 2-Naphthols via Non-covalent N-Heterocyclic Carbene Catalysis

Organic Letters, Journal Year: 2023, Volume and Issue: 25(13), P. 2323 - 2327

Published: March 30, 2023

Herein, successful utilization of non-covalent N-heterocyclic carbene (NHC) catalysis toward asymmetric aminative dearomatization naphthols is presented. The NHC-catalyzed process offers enantioselective synthesis cyclic enones possessing a nitrogen-containing α-quaternary stereocenter. reaction applies to various functionalized substrates including acid-labile groups and shown be scalable. Substrate activation via an O-H···NHC hydrogen-bonding interaction suggested based on the results obtained in mechanistic studies.

Language: Английский

Diabetic Retinopathy: Current Understanding, Mechanisms and Treatment Strategies

Journal for Research in Applied Sciences and Biotechnology, Journal Year: 2024, Volume and Issue: 3(2), P. 252 - 260

Published: May 25, 2024

Researchers have been assuming about the possible connection between eye and central nervous system (CNS) for a considerable amount of time. This is primarily due to fact that considered be an extension brain, which reasonable assumption. The neural tube beginning both structures, neurons are building blocks structures. Retinal ganglionic cells, also known as RGCs, specific type cell found in retina. These cells responsible receiving light signals from environment around them then transmitting photoreceptors, involved process vision. retina, inside eye, converting into electrical impulses, sent brain through optic nerve. Glaucoma, age-related macular degeneration (AMD), diabetic retinopathy only few illnesses can caused by chronic progressive neurodegeneration more prevalent older people. It elderly who most likely affected these disorders; nevertheless, younger people susceptible may experience permanent vision loss or reduction their eyesight. In cases, neurodegenerative disorders characteristic CSN characterised common symptoms cause partially understood. Although certain risk factors identified, they do not account all instances. On other hand, according number studies, several (CNS), such Alzheimer's disease (AD) Parkinson's (PD), significant mortality morbidity on global scale, display distinctive alterations at ocular level. helpful aware potential linkages order better understanding mechanics onset occurs. addition, experts yet reached consensus regarding various disorders. this overview, discussed detail, with particular focus interaction eye. At some point future, in-depth could assistance development innovative treatments help reduce prevent blindness improve quality life.

Language: Английский

Therapeutic Approaches of Nutraceuticals in Neurological Disorders: A Review

Journal for Research in Applied Sciences and Biotechnology, Journal Year: 2024, Volume and Issue: 3(2), P. 261 - 281

Published: May 25, 2024

A big problem in healthcare around the world is neurological illnesses. There a huge and financial burden on society worldwide due to dramatically increased risk of chronic sickness diseases linked with posed lifestyle changes. Fine treatment for sick illnesses few known adverse effects goal research. number functional food studies have been launched last decades an effort identify meals enhanced therapeutic activity reduced effects. As result, research into nutraceutical therapy illness prevention various extraction procedures disorders has underway. Progressive memory loss characterises Alzheimer's disease (AD), neurodegenerative disorder. The pharmaceutical options available today are expensive, come unwanted side effects, short supply. Scientists researchers noticed that nutraceuticals impact. anti-Alzheimer's efficacy was examined clinical preclinical investigations. study new targets, such as pathophysiological mechanisms unique cascades, resulted from growing understanding AD pathogenesis. Therefore, most effective well-known will be showcased present development, together brief involving antioxidants, autophagy control, anti-inflammatory, mitochondrial homeostasis, more. Nutraceuticals real-world impacts, getting your hands phytochemicals other vital bioactive ingredients therapeutically active foods top priority. Because this, term "functional foods" muddied replaced similar ones "pharmafoods," "medifoods," "vita foods," or "medicinal foods." high demand counteract interventions, there urgent need stick healthy options. may play preventative role therapies demonstrated correlation between dietary patterns factors neurodegeneration. Examining high-quality trials focus study, which touches several important topics. In light nutraceuticals' promise multi-targeted disease, it critical assess them promising lead molecules development drugs. Prospective should, according authors' understanding, take account blood-brain barrier permeability alteration, bioavailability, features randomised trials.

Language: Английский