Chem Catalysis, Год журнала: 2024, Номер unknown, С. 101159 - 101159
Опубликована: Ноя. 1, 2024
Язык: Английский
Chem Catalysis, Год журнала: 2024, Номер unknown, С. 101159 - 101159
Опубликована: Ноя. 1, 2024
Язык: Английский
Tetrahedron Chem, Год журнала: 2025, Номер unknown, С. 100124 - 100124
Опубликована: Фев. 1, 2025
Язык: Английский
Процитировано
0The 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
0The 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
2Organic 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
2The 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
4RSC 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
1The 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
0Molecular 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
0Organic 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
0Synlett, 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