A Triazole‐Substituted Aryl Iodide with Omnipotent Reactivity in Enantioselective Oxidations

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(4), P. 1479 - 1484

Published: Oct. 10, 2019

Abstract A widely applicable triazole‐substituted chiral aryl iodide is described as catalyst for enantioselective oxidation reactions. The introduction of a substituent in ortho‐position to the key its high reactivity and selectivity. Besides robust modular synthesis, main advantage this excellent performance plethora mechanistically diverse transformations, such spirocyclizations, phenol dearomatizations, α‐oxygenations, oxidative rearrangements. DFT‐calculations situ generated [hydroxy(tosyloxy)iodo]arene isomers give an initial rational observed reactivity.

Language: Английский

---

Photoinduced Three-Component Difluoroalkylation of Quinoxalinones with Alkenes via Difluoroiodane(III) Reagents

Organic Letters, Journal Year: 2022, Volume and Issue: 24(19), P. 3576 - 3581

Published: May 12, 2022

An environmentally friendly strategy for the photocatalyzed three-component reaction between quinoxalinones, alkenes, and hypervalent iodine(III) reagents is disclosed. The new designed difluoroiodane(III) reagent shows excellent reactivity, providing a wide range of difluoroalkyl-substituted quinoxaline-2(1H)-ones in moderate to yields under mild conditions. Experimental studies demonstrated that difluoroalkyl radical intermediate was involved this reaction.

Language: Английский

---

Organo-mediator enabled electrochemical transformations

Chemical Society Reviews, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

This review highlights organo-mediators that enable electrochemical reactions via outer-sphere electron transfer (ET), offering advantages such as availability, tunability, and simplified post-processing compared to direct electrolysis.

Language: Английский

---

Catalytic Cleavage of C(sp²)–C(sp²) Bonds with Rh-Carbynoids

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(39), P. 15509 - 15514

Published: Sept. 12, 2019

We report a catalytic strategy that generates rhodium-carbynoids by selective diazo activation of designed carbyne sources. found rhodium-carbynoid species provoke C(sp2)–C(sp2) bond scission in alkenes inserting monovalent carbon unit between both sp2-hybridized carbons. This skeletal remodeling process accesses synthetically useful allyl cation intermediates conduct to valuable allylic building blocks upon nucleophile attack. Our results rely on the formation cyclopropyl-I(III) able undergo electrocyclic ring-opening, following Woodward–Hoffmann–DePuy rules.

Language: Английский

---

Electrogenerated hypervalent iodine compounds as mediators in organic synthesis

Current Opinion in Electrochemistry, Journal Year: 2019, Volume and Issue: 15, P. 83 - 88

Published: March 29, 2019

Language: Английский

---

Enantioselective Construction of Tertiary Fluoride Stereocenters by Organocatalytic Fluorocyclization

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(47), P. 20048 - 20057

Published: Nov. 16, 2020

1,1-Disubstituted styrenes with internal oxygen and nitrogen nucleophiles undergo oxidative fluorocyclization reactions in situ generated chiral iodine(III)-catalysts. The resulting fluorinated tetrahydrofurans pyrrolidines contain a tertiary carbon–fluorine stereocenter. Application of new 1-naphthyllactic acid-based iodine(III)-catalyst allows the control stereocenters up to 96% ee. Density functional theory calculations are performed investigate details mechanism factors governing stereoselectivity reaction.

Language: Английский

---

Mechanism and Origins of Enantioselectivities in Spirobiindane-Based Hypervalent Iodine(III)-Induced Asymmetric Dearomatizing Spirolactonizations

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(40), P. 16046 - 16056

Published: Sept. 13, 2019

The work of Kita et al. on asymmetric oxidative dearomatization naphthol carboxylic acids to spirolactones mediated/catalyzed by a novel, conformationally rigid μ-oxo-bridged hypervalent iodine(III) species is landmark discovery in enantioselective catalysis [Kita, Y.; Angew. Chem., Int. Ed. 2008, 47, 3787. DOI: 10.1002/anie.200800464; J. Am. Chem. Soc. 2013, 135, 4558. 10.1021/ja401074u]. We have investigated the detailed mechanism this important transformation using density functional theory. Calculations revealed that proton transfer from pendant acid naphthols bridging oxygen atom or ligand species, which enhances nucleophilicity and nucleofugality iodoarene, crucial for dearomatizing spirolactonization. Halogen bonding between resulting carboxylate electron-deficient center further stabilizes spirolactonization transition states. also long-neglected cleaved μ-oxo more reactive but less selective than itself naphthols. coexistence two sequential processes reaction system results lower enantioselectivity. A new stereochemical model able reproduce rationalize observed apparent enantioselectivities proposed.

Language: Английский

---

Photocatalytic Fluoro Sulfoximidations of Styrenes

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(33), P. 14134 - 14137

Published: May 16, 2020

Abstract Reactions of difluoroiodotoluene with NH‐sulfoximines provide new hypervalent iodine(III) reagents, which photocatalytically transfer a fluoro and sulfoximidoyl group onto styrenes high regioselectivity. The substrate scope is broad respect to both sulfoximines olefins. Following an operationally simple protocol, large library fluorine‐containing N‐functionalized can be accessed. Results from mechanistic investigations revealed the importance radical intermediates.

Language: Английский

---

Catalytic Enantioselective Synthesis of Difluorinated Alkyl Bromides

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(35), P. 14831 - 14837

Published: Aug. 17, 2020

We report an iodoarene-catalyzed enantioselective synthesis of β,β-difluoroalkyl bromide building blocks. The transformation involves oxidative rearrangement α-bromostyrenes, utilizing HF–pyridine as the fluoride source and m-CPBA stoichiometric oxidant. A catalyst decomposition pathway was identified, which, in tandem with structure–activity relationship studies, facilitated development improved providing higher enantioselectivity lower loadings. versatility difluoroalkyl products demonstrated via highly enantiospecific substitution reactions suitably reactive nucleophiles. origins were investigated using computed interaction energies simplified substrate structures, evidence for both CH−π π–π transition state interactions critical features.

Language: Английский

---

Catalytic Vicinal Dichlorination of Unactivated Alkenes

ACS Catalysis, Journal Year: 2019, Volume and Issue: 9(8), P. 7232 - 7237

Published: July 8, 2019

Organocatalytic strategies for the programmed, catalytic oxidation of π-bonds through regioselective halogenation remain comparatively underdeveloped. The vicinal dichlorination unactivated alkenes is a pertinent example, where stoichiometric reagents and prefunctionalization steps are often employed. This surprising given prominence 1,2-dichloro moiety in an array bioactive natural products both terrestrial marine origin. Inspired by Willgerodt's seminal discovery 1886 that PhICl2 can be generated passing Cl2(g) iodobenzene, has been designed on basis I(I)/I(III) manifold. In situ generation p-TolICl2 achieved using Selectfluor CsCl. Substrate scope, mechanistic delineation, preliminary validation enantiomeric variant established. Over century after initial Willgerodt reagent (PhICl2), operationally simple, alternative validated.

Language: Английский

---