Iron‐Catalyzed Allylic C(sp³)−H Silylation: Spin‐Crossover‐Efficiency‐Determined Chemoselectivity

Angewandte Chemie International Edition, Год журнала: 2024, Номер 63(21)

Опубликована: Март 12, 2024

Abstract The nuanced role of spin effects remains a critical gap in designing proficient open‐shell catalysts. This study elucidates an iron‐catalyzed allylic C( sp 3 )−H silylation/alkyne hydrosilylation reaction, which the state iron catalyst dictates reaction kinetics and pathway. Specifically, crossover led to alkyne hydrosilylation, whereas conservation resulted novel silylation reaction. chemoselectivity, governed by spin‐crossover efficiency, reveals unexpected dimension first realm transition‐metal‐catalyzed situ bonds, had been previously inhibited heightened reactivity alkenes reactions. Furthermore, this can either accelerate or hinder at different stages within single catalytic phenomenon scarcely documented. Moreover, we identify substrate‐assisted C−H activation mechanism, departure from known ligand‐assisted processes, offering fresh perspective on strategies.

Язык: Английский

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Iron-catalysed hydroalumination of internal alkynes

Chemical Science, Год журнала: 2022, Номер 13(26), С. 7873 - 7879

Опубликована: Янв. 1, 2022

Although research on iron-catalysed reactions has recently achieved significant progress, the activity and selectivity of iron catalysts are generally inferior to those noble-metal catalysts. The development new reactions, especially in which exhibit superior or other catalysts, is key promote catalysis. Herein, we report first protocol for hydroalumination internal alkynes. Specifically, presence bearing 2,9-diaryl-1,10-phenanthroline ligands, alkynes were stereo- regioselectively hydroaluminated with commercially available reagent diisobutylaluminum hydride. Compared metal-catalysed alkyne reported literature, following advantages: unusual amino-group-directed regioselectivity, a wide substrate scope, good functional group tolerance, high selectivity, mild reaction conditions. alkenylaluminum products prepared this way could undergo diverse array transformations, used synthesis bioactive compounds. current study expands scope catalysis, provides efficient access alkenylaluminum, discloses origin superiority thus may inspire further studies related fields.

Язык: Английский

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Perspective for Phosphine Ligands with Cyclopropane Backbone^★

Acta Chimica Sinica, Год журнала: 2023, Номер 81(7), С. 777 - 777

Опубликована: Янв. 1, 2023

Throughout the history of transition-metal catalysis, almost every breakthrough is closely related to development ligands.Therefore, catalysis roughly parallels ligand lies in heart transition metal catalysis.Since beginning homogeneous metals have been accompanied by phosphine ligands (Wilkinson's catalyst).Till now, are one most widely used types.There several key factors for popularity ligands, among which backbone plays a decisive role supporting their stability, activity and selectivity.Many privileged contain five-or six-membered rings core structures, possibly due ready-availability, low ring strain, high stability.Seven-and above membered cyclic structures flexible frameworks, many stable conformations, difficult synthesize, making them unsuitable as backbones.The cyclobutane structure has relatively strong but its conformation can be flipped, it inappropriate skeleton, too.As smallest all-carbon ring, three carbon atoms cyclopropane located same plane.Because unique electronic rigidity cyclopropane, changing substituent on any will affect substituents other two carbons.And simple synthesize modify, promising skeleton.However, surprising that with rarely studied so far, applications need further explored, too.Based types this perspective systematically summarizes reported phosphine-containing (including monophosphines, diphosphines, phosphine-heteroatoms triphosphines) backbone, catalysis.We hope draw researchers' attention cyclopropane-based thus promote catalysis.

Язык: Английский

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Catalytic N‐H Insertion Reactions with α‐Diazoacetates: An Efficient Method for Enantioselective Amino Acid Synthesis

ChemCatChem, Год журнала: 2023, Номер 15(15)

Опубликована: Май 30, 2023

Abstract As the monomers of proteins, amino acids are critical in chemistry and biology, playing important roles multiple fields such as synthetic chemistry, medicinal materials chemistry. Unlike proteinogenic acids, unnatural can be difficult to obtain from living organisms generally synthesized chemically. Recently, a method involving asymmetric N−H bond carbene insertion reaction with α‐diazoacetates precursor has shown high enantioselectivity good functional group tolerance, allowing for facile synthesis natural introduction new concepts catalysis.

Язык: Английский

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Wittig/B─H insertion reaction: A unique access to trisubstituted Z -alkenes

Science Advances, Год журнала: 2023, Номер 9(37)

Опубликована: Сен. 13, 2023

The Wittig reaction, which is one of the most effective methods for synthesizing alkenes from carbonyl compounds, generally gives thermodynamically stable

Язык: Английский

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Enantioselective copper-catalyzed B–H bond insertion reaction of α-diazo phosphonates to access chiral α-boryl phosphonates

Chemical Science, Год журнала: 2024, Номер 15(19), С. 7130 - 7135

Опубликована: Янв. 1, 2024

Chiral phosphorus-containing compounds find applications across various fields, including asymmetric catalysis, medicinal chemistry, and materials science.

Язык: Английский

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Asymmetric Three-Component Radical Cascade Reactions Enabled by Synergistic Photoredox/Brønsted Acid Catalysis: Access to α-Amino Acid Derivatives

ACS Central Science, Год журнала: 2024, Номер 11(1), С. 36 - 45

Опубликована: Авг. 16, 2024

Multicomponent reactions (MCRs), highly sought-after methods to produce atom-, step-, and energy-economic organic syntheses, have been developed extensively. However, catalytic asymmetric MCRs, especially those involving radical species, remain largely unexplored owing the difficulty in stereoselectively regulating extraordinarily high reactivity of open-shell species. Herein, we report a conceptually novel three-component cascade reaction readily accessible glycine esters, α-bromo carbonyl compounds 2-vinylcyclopropyl ketones via synergistic photoredox/Brønsted acid catalysis, which three sequential C–C (σ/π/σ) bond-forming events occurred through addition/ring-opening/radical–radical coupling protocol, affording an array valuable enantioenriched unnatural α-amino derivatives bearing two contiguous stereogenic centers alkene moiety moderate good yield with diastereoselectivity, excellent enantioselectivity E-dominated geometry under mild conditions. The relay process, unique proton-coupled electron transfer (PCET)-promoted radical–radical coupling, is supported by mechanistic investigations quantum mechanics calculations should garner broad interest further inspire development multicomponent reactions.

Язык: Английский

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Copper‐Catalyzed Highly Enantioselective Ring‐Opening/Cyclopropanation of 1‐Silylcyclopropenes

Chinese Journal of Chemistry, Год журнала: 2025, Номер unknown

Опубликована: Июнь 3, 2025

Comprehensive Summary The chiral cyclopropane framework is a crucial structural motif in bioactive molecules such as pharmaceuticals and natural products. Asymmetric cyclopropanation of alkenes via transition metal‐catalyzed carbene transfer represents one the most direct approaches for synthesizing cyclopropanes. While significant progress has been made asymmetric α‐C‐substituted carbenes, highly enantioselective α‐silyl which possess greater transformation potential, remains largely unexplored. In this study, we report Cu(I)/chiral bisoxazoline catalytic system that enables cyclopropanation/Cope rearrangement reactions between α‐silyl‐α‐alkenyl carbenes (generated from ring opening 1‐silyl cyclopropene) alkenes. This methodology provides access to series cyclopropylsilanes containing stereogenic quaternary carbon centers well allylic silane moieties cycloheptadienylsilanes, thereby expanding diversity organosilicon compounds. Theoretical calculations reveal rate‐determining step involves cyclopropene, where silyl group not only dictates regioselectivity but also significantly influences stereoselectivity reaction through its steric rigid properties.

Язык: Английский

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Enantioselective Synthesis of Unnatural Carbamate-Protected α-Alkyl Amino Esters via N–H Bond Insertion Reactions

ACS Catalysis, Год журнала: 2022, Номер 12(21), С. 13143 - 13148

Опубликована: Окт. 13, 2022

We have developed a method for highly enantioselective N–H bond insertion reactions of α-alkyl-α-diazoacetates and various carbamates cooperatively catalyzed by TpCu, where Tp = (hydrotris(4,5-bromopyrazolyl)borate), chiral spiro phosphoric acid. These provide straightforward access to unnatural optically active N-carbonate α-alkyl-α-amino esters, which are widely used in artificial peptide synthesis. This mild uses readily available starting materials features broad substrate scope, good functional group tolerance, high yields (58–88%), enantioselectivities (90–96% ee). The combination the neutral copper catalyst TpCu acid ensures success reaction inhibiting β-H migration carbene intermediate promoting proton transfer an enolate intermediate.

Язык: Английский

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Highly Enantioselective Brønsted Acid Catalyzed Heyns Rearrangement

Angewandte Chemie International Edition, Год журнала: 2022, Номер 62(1)

Опубликована: Ноя. 1, 2022

Herein we report the first method for highly enantioselective Brønsted acid catalyzed Heyns rearrangements. These reactions, by a chiral spiro phosphoric acid, afforded synthetically valuable α-aryl-α-aminoketones which cannot be obtained means of previously reported rearrangement methods. This features low catalyst loadings, high yields and enantioselectivities, making these reactions practical. We used to efficiently synthesize various amines, including some biologically active molecules. experimentally proved that acid-catalyzed rearrangements proceeded via proton-transfer process involving an enol intermediate stereocontrol was realized during step.

Язык: Английский

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