Ligand Effects in Carboxylic Ester- and Aldehyde-Assisted β-C–H Activation in Regiodivergent and Enantioselective Cycloisomerization–Hydroalkenylation and Cycloisomerization–Hydroarylation, and [2 + 2 + 2]-Cycloadditions of 1,6-Enynes DOI
Kiron Kumar Ghosh, T. V. RajanBabu

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(27), С. 18753 - 18770

Опубликована: Июнь 27, 2024

Herein, we report room temperature, atom-economic protocols for high regio- and enantioselective tandem cycloisomerization–hydroarylation cycloisomerization–hydroalkenylation of 1,6-enynes leading to vicinal carba-functionalized pyrrolidines, tetrahydrofurans, cyclopentanes. The latter steps in these processes involve carbonyl-coordination-assisted ortho-C–H activation aromatic aldehydes esters, and, a similar, yet rarely seen, β-C–H the case acrylates. Synthetically useful versions such reactions are rare limited C2–H indoles pyrroles. A similar reaction is also observed with N-vinylphthalimide, which has carbonyl group suitable C–H activation. dibenzooxaphosphole ligand, (2S,2S′,3S,3S′)-MeO-BIBOP was uniquely identified as crucial achieving challenging enantioselectivity. This methodology gives access substituted five-membered carbo- heterocyclic compounds good yields excellent enantioselectivities under low catalyst loading. primary KIE 3.5 an intermolecular competition experiment methyl benzoate d5-methyl benzoate, indicates that cleavage turnover-limiting step this process. Unlike acrylates, undergoes exclusive hydroalkenylation, β, γ-unsaturated ester, but-3-enoate, highly cycloisomerization-coupling sequence 1,6-enyne giving either [2 + 2 2]-cycloaddition (S, S)-BDPP or hydroalkenylation (2S,2′S,3S,3′S)-MeO-BIBOP depending on ligand employed. (E)-configuration newly formed double bond at terminal alkynyl carbon (of starting enyne) product β,γ-unsaturated ester suggests more classical migratory insertion-β-hydride elimination route formation product.

Язык: Английский

Photoassisted Cobalt-Catalyzed Asymmetric Reductive Grignard-Type Addition of Aryl Iodides DOI
Xuan‐Feng Jiang, Hao Jiang, Qian Yang

и другие.

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(18), С. 8347 - 8354

Опубликована: Апрель 28, 2022

Grignard addition is one of the most important methods used for syntheses alcohol compounds and has been known over a hundred years. However, research on asymmetric catalysis relies use organometallic nucleophiles. Here, we report first visible-light-induced cobalt-catalyzed reductive Grignard-type synthesizing chiral benzyl alcohols (>50 examples, up to 99% yield, ee). This methodology advantages mild reaction conditions, good functionality tolerance, excellent enantiocontrol, avoidance mass metal wastes, precious catalysts. Kinetic realization studies suggested that migratory insertion an aryl cobalt species into aldehyde was rate-determining step reaction.

Язык: Английский

Процитировано

92
Photoinduced Cobalt-Catalyzed Desymmetrization of Dialdehydes to Access Axial Chirality DOI
Hao Jiang,

Xiang‐Kui He,

Xuan‐Feng Jiang

и другие.

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(12), С. 6944 - 6952

Опубликована: Март 15, 2023

Enantioselective metallaphotoredox catalysis, which combines photoredox catalysis and asymmetric transition-metal has become an effective approach to achieve stereoconvergence under mild conditions. Although many impressive synthetic approaches have been developed access central chirality, the construction of axial chirality by still remains underexplored. Herein, we report two visible light-induced cobalt-catalyzed reductive couplings biaryl dialdehydes synthesize axially chiral aldehydes (60 examples, up 98% yield, >19:1 dr, >99% ee). This protocol shows good functional group tolerance, broad substrate scope, excellent diastereo- enantioselectivity.

Язык: Английский

Процитировано

80
Dynamic Kinetic Reductive Conjugate Addition for Construction of Axial Chirality Enabled by Synergistic Photoredox/Cobalt Catalysis DOI
Wei Xiong, Xuan‐Feng Jiang, Wencheng Wang

и другие.

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(14), С. 7983 - 7991

Опубликована: Март 28, 2023

Conjugate addition is among the most important synthetic protocols for constructing carbon skeletons and widely used to synthesize natural products drugs. However, asymmetric catalysis studies have mainly focused on stereogenic centers arising from conjugate alkenes. Here, we report first photoinduced cobalt-catalyzed dynamic kinetic reductive reaction that enables formation of heterobiaryls with axial chirality (45 examples, up 91% yield 97% ee). This method features mild conditions, good functional-group tolerance, excellent enantiomeric control. Significantly, large amounts metal waste precious catalysts can be avoided under these conditions. Migration chiral arylcobalt species into alkene might rate-determining step based studies.

Язык: Английский

Процитировано

62
Catalytic Asymmetric Hydroalkoxylation and Formal Hydration and Hydroaminoxylation of Conjugated Dienes DOI

Shao‐Qian Yang,

Aijun Han, Yang Liu

и другие.

Journal of the American Chemical Society, Год журнала: 2023, Номер 145(7), С. 3915 - 3925

Опубликована: Фев. 10, 2023

The straightforward construction of stereogenic centers bearing unprotected functional groups, as in nature, has been a persistent pursuit synthetic chemistry. Abundant applications free enantioenriched allyl alcohol and hydroxylamine motifs have made the asymmetric hydration hydroaminoxylation conjugated dienes from water hydroxylamine, respectively, intriguing efficient routes that have, however, unachievable thus far. A fundamental challenge is failure to realize transition-metal-catalyzed enantioselective C–O bond constructions via hydrofunctionalization dienes. Here, we perform comprehensive study toward stereoselective formal by synthesizing set new P,N-ligands identifying an aryl-derived oxime surrogate for both hydroxylamine. Asymmetric hydroalkoxylation with also elucidated. Furthermore, versatile derivatizations following provide indirect but concise hydrophenoxylation, hydrofluoroalkoxylation, hydrocarboxylation unreported Finally, ligand-to-ligand hydrogen transfer process proposed based on results preliminary mechanistic experiments.

Язык: Английский

Процитировано

44
Chiral Aldehyde/Palladium Catalysis Enables Asymmetric Branched-Selective Ring-Opening Functionalization of Methylenecyclopropanes with Amino Acid Esters DOI
Fang Zhu, Hui He, Wen Wei

и другие.

Journal of the American Chemical Society, Год журнала: 2025, Номер unknown

Опубликована: Янв. 10, 2025

Achieving catalytic asymmetric functionalization of methylenecyclopropanes (MCPs) by selective C–C bond cleavage is a notable challenge due to the intricate reaction partners involved. In this work, we report that chiral aldehyde/palladium combined catalysis enables MCPs with NH2-unprotected amino acid esters. This proceeds through regiospecific branched ring-opening mechanism, resulting in optically active α,α-disubstituted α-amino esters bearing nonconjugated terminal alkene units. Mechanism studies indicate pathways are irreversible and ultimate regioselectivity governed palladium catalysis. The products can be utilized construction dihydropyrazoles, α-methyl aspartic derivatives, analogues VPC01091 BMS-986104.

Язык: Английский

Процитировано

3
Enantioselective Radical Addition/Cross‐Coupling of Organozinc Reagents, Alkyl Iodides, and Alkenyl Boron Reagents DOI
Matteo Chierchia, Peilin Xu, Gabriel J. Lovinger

и другие.

Angewandte Chemie International Edition, Год журнала: 2019, Номер 58(40), С. 14245 - 14249

Опубликована: Авг. 7, 2019

Abstract A hybrid transition‐metal/radical process is described that results in the addition of organozinc reagents and alkyl halides across alkenyl boron an enantioselective catalytic fashion. The reaction can be accomplished both intermolecularly intramolecularly, providing useful product yields high enantioselectivities manifolds.

Язык: Английский

Процитировано

116
Regio- and Stereoselective Reductive Coupling of Alkynes and Crotononitrile DOI
Kun Cui, Yanlin Li, Gongqiang Li

и другие.

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(50), С. 23001 - 23009

Опубликована: Дек. 8, 2022

A new regio- and stereoselective reductive coupling of alkynes crotononitrile has been developed via visible light organophotoredox cobalt dual catalysis. variety enantioenriched homoallylic nitriles bearing a stereodefined trisubstituted alkene have easily synthesized with good to excellent (up >20:1 rr), stereo- (>20:1 E/Z), enantioselectivity 98% ee) control under mild conditions. The corresponding nitrile products were smoothly converted into various chiral building blocks. Remarkably, simple organic base together water utilized as hydrogen sources in this photoinduced reaction.

Язык: Английский

Процитировано

40
Asymmetric Cross-Coupling of Aldehydes with Diverse Carbonyl or Iminyl Compounds by Photoredox-Mediated Cobalt Catalysis DOI

Zhiyong Chi,

Jia-Bin Liao,

Xiuliang Cheng

и другие.

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(15), С. 10857 - 10867

Опубликована: Апрель 8, 2024

The asymmetric cross-coupling of unsaturated bonds, hampered by their comparable polarity and reactivity, as well the scarcity efficient catalytic systems capable diastereo- enantiocontrol, presents a significant hurdle in organic synthesis. In this study, we introduce highly adaptable photochemical cobalt catalysis framework that facilitates chemo- stereoselective reductive cross-couplings between common aldehydes with broad array carbonyl iminyl compounds, including N-acylhydrazones, aryl ketones, aldehydes, α-keto esters. Our methodology hinges on synergistic mechanism driven photoredox-induced single-electron reduction subsequent radical–radical coupling, all precisely guided chiral catalyst. Various optically enriched β-amino alcohols unsymmetrical 1,2-diol derivatives (80 examples) have been synthesized good yields (up to 90% yield) high stereoselectivities >20:1 dr, 99% ee). Of particular note, approach accomplishes unattainable transformations disparate partners without reliance any external photosensitizer, thereby further emphasizing its versatility cost-efficiency.

Язык: Английский

Процитировано

18
Desymmetrization–Addition Reaction of Cyclopropenes to Imines via Synergistic Photoredox and Cobalt Catalysis DOI

Xiang‐Kui He,

Liang‐Qiu Lu,

Bao-Ru Yuan

и другие.

Journal of the American Chemical Society, Год журнала: 2024, Номер 146(28), С. 18892 - 18898

Опубликована: Июль 5, 2024

Herein, we designed a reaction for the desymmetrization-addition of cyclopropenes to imines by leveraging synergy between photoredox and asymmetric cobalt catalysis. This protocol facilitated synthesis series chiral functionalized cyclopropanes with high yield, enantioselectivity, diastereoselectivity (44 examples, up 93% yield >99% ee). A possible mechanism involving cyclopropene desymmetrization Co-H species imine addition Co-alkyl was proposed. study provides novel route important extends frontier metallaphotoredox

Язык: Английский

Процитировано

17
Enantioselective C–H bond functionalization under Co(iii)-catalysis DOI

Bholanath Garai,

Abir Das,

Doppalapudi Vineet Kumar

и другие.

Chemical Communications, Год журнала: 2024, Номер 60(25), С. 3354 - 3369

Опубликована: Янв. 1, 2024

Enantioselective C–H functionalization relies on 4d and 5d metals, but with their depletion, sustainable alternatives using 3d metals are crucial.

Язык: Английский

Процитировано

14