Singly and doubly oxidized carbenes and their applications in catalysis DOI

Allan R. Day,

Mehdi Abdellaoui, Michèle Soleilhavoup

и другие.

Chem Catalysis, Год журнала: 2024, Номер unknown, С. 101159 - 101159

Опубликована: Ноя. 1, 2024

Язык: Английский

Construction of all-carbon quaternary center by NHC-catalyzed Heck-type C–H tertiary alkylation DOI Creative Commons

Tinglan Liu,

Pan Yue, Chengming Wang

и другие.

Tetrahedron Chem, Год журнала: 2025, Номер unknown, С. 100124 - 100124

Опубликована: Фев. 1, 2025

Язык: Английский

Процитировано

0

Mechanism and Origins of Regio- and Stereoselectivities of NHC-Catalyzed Dearomative Annulation of Benzoazoles and Cinnamaldehydes from DFT DOI
Yan Li,

Yanlong Kang,

Junjie Xiao

и другие.

The Journal of Physical Chemistry A, Год журнала: 2025, Номер unknown

Опубликована: Март 5, 2025

A theoretical study on the mechanism, regioselectivity, and enantioselectivity of NHC-catalyzed dearomatizing annulation benzoxazoles with enals has been conducted using density functional theory calculations. Our calculated results indicate that favored mechanism occurs through eight reaction steps: initial binding NHC to enals, followed by formation Breslow intermediate via proton transfer. Subsequent oxidation generates α,β-unsaturated acylazolium intermediate, which can undergo Michael addition benzoxazoles. Sequential protonation/deprotonation/cyclization produces six-membered cyclic undergoes catalyst elimination, leading final product. DABCO·H+ was found play important roles in transfer cyclization. Without DABCO·H+, energy barrier up 44.2 kcal/mol for step 2 is too high be accessible. With corresponding value lowered 18.6 kcal/mol. The cyclization 7.4 DABCO·H+. determines both regioselectivity. According NCI analysis, controlled strong interactions (such as C-H···O, C-H···N, π···π) between We also discuss solvent substituent effects role NHC. mechanistic insights obtained present would help improving current systems or designing new synthetic routes.

Язык: Английский

Процитировано

0

Visible-Light-Induced Regioselective Cascade Radical Cyclization of α-Bromocarbonyls: Access to Benzazepine Derivatives DOI
Nengneng Zhou,

Fangli Zhao,

Lei Wang

и другие.

The Journal of Organic Chemistry, Год журнала: 2024, Номер 89(4), С. 2238 - 2246

Опубликована: Янв. 31, 2024

Visible-light-induced regioselective cascade radical cyclization of α-bromocarbonyls for the synthesis benzazepine derivatives is described. In presence fac-Ir(ppy)3 (2.0 mol %) as a photocatalyst, 2,6-lutidine base, and dichloromethane solvent, reactions proceed smoothly to afford seven-membered rings in good yields. This protocol features broad substrate scope, excellent functional group tolerance, mild reaction conditions. Preliminary mechanistic studies reveal that generation α-carbon more prone react with 1,1-diphenylethylene tethered acrylamide generate stable heterocycle.

Язык: Английский

Процитировано

2

N-Heterocyclic Carbene Catalysis for Polycyclic Benzazepines Assembly: Regioselective Intramolecular Tandem Radical Cyclization DOI
Zhiming Feng, Lili Wu,

Cong‐Ying Zhou

и другие.

Organic Letters, Год журнала: 2024, Номер 26(42), С. 9068 - 9072

Опубликована: Окт. 11, 2024

A variety of polycyclic benzazepines were rapidly constructed by NHC-catalyzed regioselective redox-neutral intramolecular tandem cyclization. Initial mechanistic studies revealed that a SET radical process was possibly involved.

Язык: Английский

Процитировано

2

NHC-Catalyzed Tandem Reaction: A Strategy for the Synthesis of 2-Pyrrolidinone-Functionalized Phenanthridines DOI
Nengneng Zhou, Lei Wang,

Fangli Zhao

и другие.

The Journal of Organic Chemistry, Год журнала: 2023, Номер 88(23), С. 16556 - 16565

Опубликована: Ноя. 16, 2023

Herein, an N-heterocyclic carbene (NHC)-catalyzed tandem cyclization/addition/cyclization reaction of 2-isocyanobiaryls and α-bromo-N-cinnamylamides for the synthesis 2-pyrrolidinone-functionalized phenanthridines is developed. This protocol features a radical cascade process, broad substrate scope, good functional group compatibility under metal- oxidant-free conditions.

Язык: Английский

Процитировано

4

DFT investigation of the mechanism and role of N-heterocyclic carbene (NHC) in constructing asymmetric organosilanes using NHC-catalyzed [4+2] cycloaddition reaction DOI Creative Commons
Batoul Alipour

RSC Advances, Год журнала: 2024, Номер 14(48), С. 35475 - 35489

Опубликована: Янв. 1, 2024

The mechanism and origin of stereoselectivity for the synthesis asymmetric organosilanes using NHC are theoretically investigated.

Язык: Английский

Процитировано

1

Mechanism, Chemoselectivity, and Stereoselectivity of an NHC-Catalyzed Reaction of Aldehydes and Hydrazones: A DFT Study DOI
Yan Li,

Yanlong Kang,

Junjie Xiao

и другие.

The Journal of Physical Chemistry A, Год журнала: 2024, Номер 128(22), С. 4483 - 4492

Опубликована: Май 24, 2024

To elucidate the mechanism and origins of chemo- enantioselectivities reaction between aliphatic aldehydes hydrazones catalyzed by triazolium-derived NHC, density functional theory computations have been performed. According to our calculated results, whole catalytic cycle for formation dihydropyridazinones proceeds via initial nucleophilic addition NHC an aldehyde, followed concerted intramolecular proton transfer C-Cl bond cleavage. Subsequent deprotonation generates enolate intermediate. The intermediate then undergoes 1,4-addition hydrazone construct a new carbon-carbon bond. following ring-closure would lead six-membered ring intermediate, which, upon release affords final product dihydropyridazinone. computation results reveal that is significantly promoted Brønsted acid DIPEA·H

Язык: Английский

Процитировано

0

Theoretical study of [3 + 3] annulation reaction of bromoenal with β-tetralone catalysed by N-heterocyclic carbene DOI
Zhiyi Song, Zhiqiang Zhang, Yan Li

и другие.

Molecular Physics, Год журнала: 2024, Номер unknown

Опубликована: Июнь 3, 2024

N-heterocyclic carbenes (NHCs) are effective organocatalysts, which widely used in various cycloaddition reactions. Among them, the [3 + 3] reaction type can be for synthesis of six-membered ring, is also one most important methods formation carbon–carbon bonds organic chemistry. In this paper, a possible pathway stereoselective bromoenal and β-tetralone have been investigated at M06-2X/6–31G(d,p)/IEFPCM(THF) level. Our suggested mechanism includes binding NHC to bromoenal, 1,2-proton transfer, debromination, 1,3-proton shift, Michael addition, protonation, deprotonation cyclisation, regeneration. The stereochemistry determined by addition step, favourable generates R-configurational dihydropyranone. Furthermore, through use global reactivity indexes (GRIs), we able demonstrate that nucleophilicity increased NHC. mechanistic insights gained work should helpful rational design potential catalysts analogous

Язык: Английский

Процитировано

0

Base-Promoted Ring Expansion Reaction of 4-Quinolones To Access Benzazepinones DOI

Fuhao Jiang,

Rong Fan,

Bo Chen

и другие.

Organic Letters, Год журнала: 2024, Номер unknown

Опубликована: Сен. 24, 2024

4-Quinolone derivatives undergo an unexpected ring expansion reaction with α-halo esters/phosphonates/sulfones in the presence of a base, such as NaH, to produce novel benzazepinones. Under these mild and transition-metal-free conditions, most substrates gave moderate excellent yields. The could be applied gram-scale synthesis drug-like molecules that greatly accelerated our structure-activity relationship studies. A plausible mechanism was proposed.

Язык: Английский

Процитировано

0

N-heterocyclic carbene switchable radical or benzyne meditated arylation of thiols using DMF/KOtBu DOI
Ben W. Greatrex, Johannes Puschnig

Synlett, Год журнала: 2024, Номер unknown

Опубликована: Ноя. 4, 2024

Abstract A mild, metal, and photoredox-free direct arylation of alkyl aryl thiols with iodides using a DMF/KOt-Bu system has been developed. In the absence an N-heterocyclic carbene (NHC) additive, reaction proceeds via benzyne intermediate was suitable for substitution phenyl, while presence NHC or phenanthroline derivative improves regioselectivity substituted radical pathway. This protocol features inexpensive materials good substrate scope could be useful in thiols.

Язык: Английский

Процитировано

0