Rhodium-Catalyzed Regio-, Diastereo-, and Enantioselective Three-Component Carboamination of Dienes via C–H Activation

ACS Catalysis, Journal Year: 2021, Volume and Issue: 11(11), P. 6692 - 6697

Published: May 24, 2021

Reported herein is the rhodium-catalyzed enantioselective three-component coupling of arene, diene, and dioxazolone that occurs via C–H activation en route to allyl intermediate. This carboamination reaction affords chiral allylic amines in 1,2-selectivity, E-selectivity, enantioselectivity, with electrophilic amination π-allyl species being both regio- enantio-determining.

Language: Английский

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Rhodium(III)-Catalyzed Enantioselective C–H Activation/Annulation of Ferrocenecarboxamides with Internal Alkynes

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(5), P. 3083 - 3093

Published: Feb. 21, 2022

Efficient synthesis of planar chiral ferrocene-fused heterocyclic molecules is challenging in asymmetric synthesis. Herein, we report an enantioselective C–H activation/annulation ferrocenecarboxamides with internal alkynes promoted by CpRh(III) catalysis. Trisubstituted Cp-derived Rh complexes are found to be enabling catalysts, which lead a broad substrate scope good functional group compatibility. Planar pyridone products obtained high yields (up 90%) excellent enantioselectivity 99% ee). Combined experimental and computational studies support the proposed reaction mechanism.

Language: Английский

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A Class of Readily Tunable Planar‐Chiral Cyclopentadienyl Rhodium(III) Catalysts for Asymmetric C–H Activation

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(23)

Published: March 18, 2022

Chiral half-sandwich cyclopentadienyl rhodium(III) (CpRhIII ) complexes are powerful catalysts for promoting asymmetric C-H activation reactions. Their preparation normally involved linking or embedding the Cp motif to into a certain chiral backbone forge so-called ligand. However, of planar-chiral CpRhIII catalyst bearing non-chiral ligand remains formidable challenge and is rarely reported. We describe herein an unusual class rhodium ligands. Different from existing ones, this readily tunable. Ten only were prepared with ease, successfully used in two enantioselective Given its convenient synthesis high structural tunability, these expected find more utilities activation.

Language: Английский

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Mechanistically Guided Workflow for Relating Complex Reactive Site Topologies to Catalyst Performance in C–H Functionalization Reactions

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(4), P. 1881 - 1898

Published: Jan. 24, 2022

Leveraging congested catalyst scaffolds has emerged as a key strategy for altering innate substrate site-selectivity profiles in C-H functionalization reactions. Similar to enzyme active sites, optimal small molecule catalysts often feature reactive cavities tailored controlling approach trajectories. However, relating three-dimensional shape reaction output remains formidable challenge, part due the lack of molecular features capable succinctly describing complex site topologies terms numerical inputs machine learning applications. Herein, we present new set descriptors, "Spatial Molding Approachable Rigid Targets" (SMART), which have applied quantify spatial constraints an expansive library dirhodium and predict 1-bromo-4-pentylbenzene via donor/acceptor carbene intermediates. Optimal terminal methylene position was obtained with Rh2(S-2-Cl-5-MesTPCP)4 (30.9:1 rr, 14:1 dr, 87% ee), while at electronically activated benzylic increasingly favored Rh2(TPCP)4 lacking ortho-Cl, Rh2(S-PTAD)4, Rh2(S-TCPTAD)4, respectively. Intuitive global models 25 disparate were developed multivariate linear regression explicitly assess contributing roles steric congestion dirhodium-carbene electrophilicity functionalization. The workflow utilizes classification extract descriptors only conformers, nuance that may be widely applicable establishing close correspondence between ground-state model systems transition states. Broader still, SMART are amenable delineating salient reactivity other chemical biological contexts.

Language: Английский

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Catalytic, asymmetric carbon–nitrogen bond formation using metal nitrenoids: from metal–ligand complexes via metalloporphyrins to enzymes

Chemical Science, Journal Year: 2023, Volume and Issue: 14(44), P. 12447 - 12476

Published: Jan. 1, 2023

The introduction of nitrogen atoms into small molecules is fundamental importance and it vital that ever more efficient selective methods for achieving this are developed. With aim, the potential nitrene chemistry has long been appreciated but its application constrained by extreme reactivity these labile species. This liability however can be attenuated complexation with a transition metal resulting nitrenoids have unique highly versatile which includes amination certain types aliphatic C-H bonds as well reactions alkenes to afford aziridines. At least one new chiral centre typically formed in processes development catalysts exert control over enantioselectivity nitrenoid-mediated become growing area research, particularly past two decades. Compared some synthetic methods, nitrenoid notable chemists draw from diverse array metals , ranging metal-ligand complexes, bearing variety ligand types, via bio-inspired metalloporphyrins, all way through to, very recently, engineered enzymes themselves. In latter category particular, rapid progress being made, rate suggests approach may instrumental addressing outstanding challenges field. review covers key developments strategies shaped field, addition latest advances, up until September 2023.

Language: Английский

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