Understanding the Ligand Influence in the Multistep Reaction of Diazoalkanes with Palladium Complexes Leading to Carbene-Aryl Coupling

Organometallics, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 10, 2025

The reaction of diphosphino aryl complexes [Pd(C6F5)(L-L)(NCMe)](BF4) (L-L = dppe, dppp, dppb) with diazoalkanes N2CHR (R -CH=CHPh, Ph) leads to η3-allyl or η3-benzyl palladium derivatives that are the organometallic products resulting from carbene-aryl coupling. experimental trend shows is favored for dppe > dppp dppb. It involves several consecutive steps, i.e., diazoalkane coordination, nitrogen extrusion give a Pd-carbene, and migratory insertion, which experimentally inseparable, but they can be studied help DFT calculations. bulkiness bite angle ligand exert large influence in relative rate steps involved reaction, we have found carbene formation by N2 step largest barrier dppe. In contrast, coordination most energy-demanding larger dppb diphosphines. Thus, substitution controls rate, an important elemental rarely considered mechanistic studies cross coupling reactions. Since common precursors, either directly generated hydrazones, choice very facilitate entrance precursor catalytic cycle.

Language: Английский

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Iodonium ylides: an emerging and alternative carbene precursor for C–H functionalizations

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 21(1), P. 24 - 38

Published: Nov. 23, 2022

The metal-catalyzed successive activation and functionalization of arene/heteroarene is one the most fundamental transformations in organic synthesis leads to privileged scaffolds natural products, pharmaceuticals, agrochemicals, fine chemicals. Particularly, transition-metal-catalyzed C-H arenes with carbene precursors via metal migratory insertion has been well studied. As a result, diverse have evaluated, such as diazo compounds, sulfoxonium ylides, triazoles, etc. In addition, there significant developments use iodonium ylides recent years, these reactions proceed high efficiencies selectivities. This review provides comprehensive overview functionalizations, including scope, limitations, their potential synthetic applications.

Language: Английский

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Weakly Coordinating tert-Amide-Assisted Ru(II)-Catalyzed Synthesis of Azacoumestans via Migratory Insertion of Quinoid Carbene: Application in the Total Synthesis of Isolamellarins

Organic Letters, Journal Year: 2022, Volume and Issue: 24(25), P. 4536 - 4541

Published: June 23, 2022

A weakly coordinating tert-amide-directed straightforward method was developed for the synthesis of azacoumestans using corresponding azaheterocycle derivatives and diazonaphthoquinones under cheap Ru(II)-catalyzed conditions. The reaction proceeds via migratory insertion quinoid carbene subsequent Brønstead acid-mediated cyclization. optimized C2-selective offered a wide scope important azaheterocycles. Bioactive natural products like isolamellarins B were synthesized protocol. Preliminary mechanistic studies highlighted probable pathway.

Language: Английский

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Coupling partner-dependent unsymmetrical C–H functionalization of N-phenoxyacetamides leading to sophisticated spirocyclic scaffolds

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 9(17), P. 4583 - 4590

Published: Jan. 1, 2022

In this paper, a coupling partner-dependent unsymmetrical C–H functionalization of N -phenoxyacetamides leading to the formation sophisticated spirocyclic scaffolds is presented.

Language: Английский

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Rh(iii)-catalyzed selective mono- and dual-functionalization/cyclization of 1-aryl-5-aminopyrazoles with iodonium ylides

Chemical Communications, Journal Year: 2023, Volume and Issue: 60(4), P. 432 - 435

Published: Dec. 5, 2023

Highly functionalized benzodiazepine skeletons were efficiently synthesized via a Rh( iii )-catalyzed selective mono- and dual-C–H bond functionalization/cyclization reaction between readily available 1-aryl-5-aminopyrazoles iodonium ylides under.

Language: Английский

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Catalytic Stereoselective 1,2-cis-Furanosylations Enabled by Enynal-Derived Copper Carbenes

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(2), P. 1037 - 1049

Published: Jan. 8, 2024

1,2-cis-Furanosides are present in various biomedically relevant glycosides, and their stereoselective synthesis remains a significant challenge. In this vein, we have developed approach to 1,2-cis-furanosylations using earth-abundant copper catalysis. This protocol proceeds under mild conditions at room temperature employs readily accessible benchtop stable enynal-derived furanose donors. chemistry accommodates variety of alcohols, including primary, secondary, tertiary, as well mannosyl alcohol acceptors, which been incompatible with most known methods furanosylation. The resulting 1,2-cis-furanoside products exhibit high yields anomeric selectivity both the ribose arabinose series. Furthermore, is independent C2 oxygen-protecting group configuration starting donor. Experimental evidence computational studies support our hypothesis that chelation between oxygen donor an incoming nucleophile responsible for observed 1,2-cis-stereoselectivity.

Language: Английский

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Overview of Transition Metal Catalyzed Multicomponent Reactions Based on Trapping of Allylic Electrophiles

ChemCatChem, Journal Year: 2024, Volume and Issue: 16(4)

Published: Jan. 11, 2024

Abstract Multicomponent reactions provide an excellent approach toward quaternary carbon centres utilizing convergent chemical in a highly selective manner under one‐pot conditions. The reactivity of substrates and metal catalysts is carefully controlled, precluding the formation side‐products. In this context, transition catalyzed onium ylides generated via diazo precursors nucleophiles with third component (an electrophile) have garnered significant attention. Using allylic precursor as electrophilic partner provides opportunities to construct all‐carbon centres. Furthermore, presence allyl fragment multicomponent product serves pivotal handle for carrying out subsequent modifications. Several recent studies employed Rh, Pd, dual Rh/Pd catalytic systems involving alkylation that proceed synergistic or relay pathway. Although not significantly successful, few cases, asymmetric induction achieved through chiral phosphoric acids phosphine ligands. Limited substrate catalyst scope underlying mechanistic complexities posed formidable challenges, slowing advancement reactions. This review details using readily available like compounds, carbonates, (R‐OH, R‐NH 2 , etc .) forming complex organic compounds. Our primary objective discuss issues may facilitate progress field.

Language: Английский

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Cu(II)-Catalyzed Construction of Heterobiaryls using 1-Diazonaphthoquinones: A General Strategy for the Synthesis of QUINOX and Related P,N Ligands

Organic Letters, Journal Year: 2022, Volume and Issue: 24(8), P. 1631 - 1636

Published: Feb. 21, 2022

An efficient and straightforward method was developed for the synthesis of heterobiaryls using easily available N-oxides diazonaphthoquinones under cheap Cu(II) catalysis. The offered QUINOX related congeners in a simple manner. A wide scope important achieved with high site selectivity. synthesized naphthols were transformed into privileged P,N ligands. Suitable resolution methods can directly afford corresponding axially chiral heterobiaryls.

Language: Английский

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Synthesis of Tetrahydrocarbazol-4-ones via Rh(III)-Catalyzed C–H Activation/Annulation of Arylhydrazines with Iodonium Ylides

The Journal of Organic Chemistry, Journal Year: 2022, Volume and Issue: 87(12), P. 8142 - 8150

Published: June 8, 2022

The rhodium(III)-catalyzed C–H activation followed by intramolecular annulation reactions between arylhydrazines and iodonium ylides under suitable conditions has been described. Tetrahydrocarbazol-4-ones are readily achieved with moderate to excellent yields. synthetic protocol features a wide range of substrates high functional group tolerance. gram-scale reaction derivatization the product demonstrate practicality utilization this method.

Language: Английский

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Nucleophile-Controlled Trapping of Gold Carbene by Nitriles and Water: Synthesis of 5H-Pyrimido[5,4-b]indoles and 2-Benzylidene-3-indolinones

Organic Letters, Journal Year: 2024, Volume and Issue: 26(3), P. 631 - 635

Published: Jan. 12, 2024

A gold-catalyzed, nucleophile-controlled cascade reaction of N-(2-azidophenyl-ynyl)methanesulfonamides with nitriles and water is described that provides structurally diverse 5H-pyrimido[5,4-b]indoles 2-benzylidene-3-indolinones in good to excellent yields. Mechanistic studies indicate the β-sulfonamido-α-imino gold carbene key intermediate which generated through gold-catalyzed cyclization undergoes formal [4 + 2] annulation intramolecular SN2′ type water, respectively.

Language: Английский

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