Radical NHC Catalysis

ACS Catalysis, Год журнала: 2022, Номер 12(19), С. 11984 - 11999

Опубликована: Сен. 19, 2022

Radical/radical cross-coupling reactions represent an efficient and straightforward approach for the construction of chemical bonds accordingly have drawn increasing attention over past decades. In order to achieve synthetically useful transformations, a persistent radical should be coupled with transient in accordance effect (PRE). However, known radicals outnumber by far types free radicals, which limits widespread application PRE, until today. Thus, development between has been focus, meanwhile transition-metal catalysis successfully implemented artificially prolong lifetimes, allowing their utilization formal radical/radical cross-couplings. Complementary research field recently uncovered that organocatalytically generated NHC-derived ketyl are type catalytically radicals. NHC-catalyzed transformations aldehydes carboxylic acid derivatives enabled disclosure ever-increasing number interesting reactions, different from traditional ionic processes, offering otherwise inaccessible activation modes. These discoveries opened door NHC organocatalysis manipulation reactions. Due its obvious potential synthetic organic chemistry, it is timely provide perspective on this emerging field.

Язык: Английский

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Recent advances in combining photo- and N-heterocyclic carbene catalysis

Chemical Science, Год журнала: 2023, Номер 14(46), С. 13367 - 13383

Опубликована: Янв. 1, 2023

This review summarizes recent advances in combining photo- and N-heterocyclic carbene catalysis, as well provides an outlook on future opportunities challenges.

Язык: Английский

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Regiodivergent C−H Acylation of Arenes by Switching from Ionic‐ to Radical‐Type Chemistry Using NHC Catalysis

Angewandte Chemie International Edition, Год журнала: 2023, Номер 62(27)

Опубликована: Апрель 24, 2023

The Friedel-Crafts acylation reaction, which belongs to the class of electrophilic aromatic substitutions is a highly valuable and versatile reaction in synthesis. Regioselectivity predictable determined by electronic as well steric factors (hetero)arene substrate. Herein, radical approach for arenes heteroarenes presented. C-H achieved through mild cooperative photoredox/NHC catalysis with cross-coupling an arene cation NHC-bound ketyl key step. As compared classical acylation, regiodivergent outcome observed upon switching from ionic mode. In these divergent reactions, aroyl fluorides act reagents both process.

Язык: Английский

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Homologation of Ketones: Direct Transformation of Alkyl Ketones to Aryl Ketones via Photoredox Catalyzed Deacylation-Aroylation Sequence

Organic Letters, Год журнала: 2024, Номер 26(32), С. 6915 - 6920

Опубликована: Авг. 8, 2024

Ketones, as essential functional group skeletons, have garnered significant interest due to their diverse transformations. Herein, we describe a versatile photoredox catalyzed deacylation-aroylation strategy that enables the direct transformation of alkyl ketones aryl ketones. This process involves deacylation dihydroquinazolinones derived from generate radicals, followed by subsequent NHC-catalyzed or NHC-mediated radical aroylation.

Язык: Английский

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Radical Acylation of Alkenes by NHC‐Organocatalysis

European Journal of Organic Chemistry, Год журнала: 2023, Номер 26(48)

Опубликована: Окт. 11, 2023

Abstract N ‐Heterocyclic carbene (NHC) catalyzed radical‐radical reactions have been proven to be powerful strategies for assembling ketyl‐containing compounds via single electron transfer (SET) pathway under either thermal conditions or photoredox conditions. In this context, acylation of alkenes radical relay NHC‐organocatalysis has also opened a new window the difunctionalization construct valuable molecules in organic synthesis. review, advances and progress were summarized according different ways generation key NHC‐bound ketyl‐type radicals. Furthermore, reaction scopes, limitations mechanisms discussed based on types catalytic systems. Conclusions perspectives put forward at end.

Язык: Английский

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Construction of C(CO)–C(CO) Bond via NHC-Catalyzed Radical Cross-Coupling Reaction

Organic Letters, Год журнала: 2023, Номер 25(11), С. 1829 - 1833

Опубликована: Март 10, 2023

A C(sp2)–C(sp2) bond can be constructed via a photoredox/N-heterocyclic carbene (NHC)-cocatalyzed radical cross-coupling reaction, which provides complementary strategy to classic electron pair processes. The present protocol represents the first example of an NHC-catalyzed two-component reaction involving C(sp2)-centered species. decarboxylative acylation oxamic acid with acyl fluoride was conducted under mild conditions and allowed preparation variety useful α-keto amides, including sterically congested ones.

Язык: Английский

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Synthesis of β-Ketonitriles via N-Heterocyclic-Carbene-Catalyzed Radical Coupling of Aldehydes and Azobis(isobutyronitrile)

Organic Letters, Год журнала: 2023, Номер 25(18), С. 3325 - 3329

Опубликована: Апрель 27, 2023

Herein, an NHC (N-heterocyclic carbene)-catalyzed radical coupling reaction between aldehydes and azobis(isobutyronitrile) (AIBN) has been developed. This method provides efficient convenient approach for the synthesis of β-ketonitriles containing a quaternary carbon center (31 examples, up to >99% yield) utilizing commercially available substrates. protocol features broad substrate scope, good functional group tolerance, high efficiency under metal-free mild conditions.

Язык: Английский

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Cross‐Coupling Reaction of Alkyl Halides with Aldehydes through NHC Catalysis

ChemCatChem, Год журнала: 2024, Номер 16(15)

Опубликована: Фев. 21, 2024

Abstract During the past decades, N ‐heterocyclic carbene (NHC)‐catalyzed reactions have emerged as a versatile tool in synthetic chemistry. In particular, NHC‐catalyzed cross‐coupling reaction has been significantly developed many respects, including new development and mechanistic investigation. This concept article presents recent advances towards direct of aldehydes with alkyl halides enabled by NHC organocatalysis.

Язык: Английский

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N-Heterocyclic Carbene-Catalyzed Synthesis of Pentafluorophenyl Sulfides

Chinese Journal of Organic Chemistry, Год журнала: 2024, Номер 44(2), С. 622 - 622

Опубликована: Янв. 1, 2024

An efficient method for the construction of C(sp 2 )-S bond has been developed.The stable N-heterocyclic carbene 1,3-bis(2,6-dissopropylphenyl)-imidazole-2-ylidene can activate C -Si pentafluorophenyl trimethylsilicon effectively to initiate nucleophilic substitution reaction with thiosulfonic ester, producing sulfide products in 34%～98% yields.Keywords carbene; C-S bond; 碳-硫(C-S)键广泛存在于天然产物、生物活性化 合物、药物以及功能材料中, 因此 键的构建一直 是有机合成领域中的研究热点 [1] .在过去几十年中, 过 渡金属催化的交叉偶联反应、插入反应、硫代羰基化、 亲核加成反应等已经被广泛地用于 键的构建 [2] .另外, 多氟芳烃很多为重要的结构单元, 广泛存在于药 物分子和聚合物中, 因此合成五氟芳基硫醚化合物在有 机化学中具有重要意义 [3] .在过去的几十年里, 化学家 发展了几种合成五氟苯基硫醚化合物的方法.Kita 课题 组 [4] 在 2001 年通过 TMSOTf 催化富电子芳烃与醌单-O,S-缩醛的亚磺酰化和亲核加成反应获得了五氟苯基 硫醚化合物, 但该反应需要在低温条件下进行(Scheme 1a).Shi 课题组 [5] 用 Cu(I)催化五氟苯与二芳基二硫醚发 生交叉偶联反应(Scheme 1b), 得到相应的五氟苯基硫 醚, Peng [6] Ni(0)催化硫醇和芳基碘化物分子间 交叉偶联反应快速地合成了多种五氟苯基硫醚(Scheme Sakai [7] Pd(II)/Cu(II)催化二芳基二硫醚与 芳烃的交叉偶联反应(Scheme 得到五氟苯基硫醚 化合物.此外, Shibata [8] 通过活化的 α-亚甲基酮、 环状 1,3-二酮、 内酰胺和内酯与 6 F 5 -DAST 的脱酰基五 氟苯基硫化反应(Scheme 得到五氟苯基环硫醚衍 生物.然而这些方法一般都需要过渡金属催化剂催化, 有的还需要高温等较为苛刻的反应条件.我们课题组 [9] 前期利用膦腈碱 t-Bu-P 4 作为强有机 Lewis 碱催化剂, 实 现了有机小分子催化下五氟苯基硅试剂与硫代磺酸酯 的亲核取代反应(Scheme 1c), 制备了多种五氟苯基硫醚 化合物, 但膦腈碱催化剂价格非常昂贵, 在实验室制备 困难, 且该催化剂对水和空气高度敏感, 实验操作需要 极其严苛的无水无氧条件.因此, 该方法的实际应用受 到了一定的限制.

Язык: Английский

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The literature of heterocyclic chemistry, part XXII, 2022

Advances in heterocyclic chemistry, Год журнала: 2025, Номер unknown

Опубликована: Янв. 1, 2025

Язык: Английский

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