Enantioselective [3+2] Annulation of Aldimines with Alkynes by Scandium‐Catalyzed C−H Activation

Angewandte Chemie International Edition, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 3, 2025

Abstract The enantioselective [3+2] annulation of readily accessible aldimines with alkynes via C−H activation is, in principle, a straightforward and atom‐efficient route for synthesizing chiral 1‐aminoindenes, which are important components wide array natural products, bioactive molecules, functional materials. However, such asymmetric transformation has remained undeveloped to date due the lack suitable catalysts. Here, we report first time using half‐sandwich scandium This protocol enabled synthesis diverse multi‐substituted 1‐aminoindene derivatives 100 % atom‐efficiency, broad substrate scope, high regio‐ enantioselectivity. Density theory (DFT) analyses have revealed that noncovalent C−H⋅⋅⋅π interaction between tert ‐Bu substituent cyclopentadienyl (Cp) ligand phenyl ring an aromatic aldimine played role achieving level work not only offers efficient selective new family but also unprecedented insights into enantioselectivity control Cp‐ligated metal

Language: Английский

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Rhodium(iii)-catalyzed intermolecular [3+3] annulation of benzoxazines with quinone compounds: access to spiro-heterocyclic scaffolds

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(77), P. 11520 - 11523

Published: Jan. 1, 2023

A rhodium(III)-catalyzed redox-neutral spiroannulation approach to access the spiro[benzo[b][1,4]oxazine-benzo[c]chromene skeleton is described in this contribution. variety of spiro[5.5]-heterocyclic scaffolds were obtained moderate excellent yields under mild conditions. Key features protocol are good substrate scope, silver-free conditions, low catalyst loadings, easy handling air and 100% atom economy. Furthermore, scale-up reactions late-stage derivatizations highlight potential synthetic utility methodology.

Language: Английский

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Regioselective [3+2]‐Spiroannulation and [4+n]‐Annulation Approaches through Activation of C−H Bond Facilitated by Ru(II) as Catalyst: Role of Solvent Selectivity

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(8), P. 1863 - 1876

Published: Feb. 21, 2024

Abstract Ru(II)‐catalyzed and solvent‐switched [3+2]‐spiroannulation [4+n] (n=1, 2, 3) annulations of 2‐aryl quinazolinone or 2‐aryl‐2,3‐dihydrophthalazine‐1,4‐diones with ynones alkynyl alcohol 1,3‐diynes under mild reaction conditions have been analyzed. These reactions take place in the presence appropriate solvent features a redox‐neutral pathway. Ynone serves as an ‘atypical one‐carbon unit’ [4+1] annulation generates tetrasubstituted carbon center bearing diverse heterocycles through [3+2] strategies. Post transformations synthesized spiro‐products augments potential developed methodology.

Language: Английский

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Enantioselective [3+2] Annulation of Aldimines with Alkynes by Scandium‐Catalyzed C−H Activation

Angewandte Chemie, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 3, 2025

Abstract The enantioselective [3+2] annulation of readily accessible aldimines with alkynes via C−H activation is, in principle, a straightforward and atom‐efficient route for synthesizing chiral 1‐aminoindenes, which are important components wide array natural products, bioactive molecules, functional materials. However, such asymmetric transformation has remained undeveloped to date due the lack suitable catalysts. Here, we report first time using half‐sandwich scandium This protocol enabled synthesis diverse multi‐substituted 1‐aminoindene derivatives 100 % atom‐efficiency, broad substrate scope, high regio‐ enantioselectivity. Density theory (DFT) analyses have revealed that noncovalent C−H⋅⋅⋅π interaction between tert ‐Bu substituent cyclopentadienyl (Cp) ligand phenyl ring an aromatic aldimine played role achieving level work not only offers efficient selective new family but also unprecedented insights into enantioselectivity control Cp‐ligated metal

Language: Английский

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Synthesis of Polycyclic Heteroarenes via Rh(III)-Catalyzed Twofold C-H Activation of 3-Aryl-2H-benzo[b][1,4]oxazines and Annulation with α-Diazo-β-ketoesters

The Journal of Organic Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: March 14, 2025

An efficient Rh(III)-catalyzed annulation between 3-aryl-2H-benzo[b][1,4]oxazines and α-diazo-β-ketoesters was developed, affording a series of polycyclic heteroarenes in moderate to excellent yields with good functional group compatibility. The procedure featured high efficiency, redox neutrality, twofold ortho-C-H activation, dual [4 + 2] annulation. Moreover, several important intermediates products have been isolated as powerful evidence for the proposed reaction mechanism.

Language: Английский

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Ruthenium(II)-Catalyzed C–H Activation/Annulation of 5-Phenyl-pyrroline-2-carboxylates with Alkynes: Synthesis of 2,3-Diphenylspiro-[indene-1,2′pyrrolidine]carboxylate Derivatives

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: May 8, 2025

While saturated nitrogen heterocycles are privileged scaffolds, their streamlined catalytic synthesis with unsymmetrical substitution patterns remains a daunting challenge. Herein, we report the ruthenium(II)-catalyzed of spiro[indene-proline] derivatives via C-H activation/annulation 5-phenyl-pyrroline-2-carboxylates alkynes. The protocol utilized imine coordination, resulting in high reaction yields wide range functional group tolerance, scalability, and scaffold diversity. This annulation was successful even various biologically active pharmacophores. featured reversible metalation step suggested possibility base-assisted internal electrophilic pathway.

Language: Английский

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Synthesis of indene-fused spiro-dibenz(ox)azepines via Rh(iii)-catalyzed cascade regioselective C–H activation/annulation

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(50), P. 7751 - 7754

Published: Jan. 1, 2023

We report an unprecedented atom-economic one-pot Cp*Rh(III)-catalyzed regioselective [3+2]-spiroannulation reaction between dibenz(ox)azepines and ynones, allowing the synthesis of biologically relevant novel spirocyclic under operationally simple mild conditions. The proceeds without any silver additive or external oxidant implementing a redox-neutral pathway. A broad substrate scope with diverse functional group tolerance permitted wide spectrum indene-containing in good to excellent yields. Also, we showcased detailed mechanistic studies justify formation spirocycles. In addition, synthetic utility this process was also demonstrated by modular various steroid conjugates.

Language: Английский

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Straightforward Access to Free β^2,3,3‐Amino Acids through One Pot C‐H Activation/C−C Cleavage

Chemistry - A European Journal, Journal Year: 2024, Volume and Issue: 30(18)

Published: Jan. 18, 2024

The first synthesis of unnatural β

Language: Английский

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Rh(iii)-catalyzed [3 + 2] spiroannulation of 2,3-dihydro-1,4-benzoxazines with 4-hydroxy-2-alkynoates throughortho-C–H bond functionalization

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 21(30), P. 6169 - 6173

Published: Jan. 1, 2023

Rhodium(III)-catalyzed [3 + 2]-spiroannulation of 2-aryl-1,4-benzoxazines with 4-hydroxy-2-alkynoates has been developed for the synthesis highly rigid spirolactones in good yields high regioselectivity. The reaction proceeds through a cascade C-H activation followed by annulation and lactonization. In this approach, two C-C C-O bonds are formed single step. This is first report on spiroannulation 2,3-dihydro-1,4-benzoxazines 4-hydroxy-2-alkynoates.

Language: Английский

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Synthesis of spiropyrans via Ru(ii)-catalyzed coupling of 3-aryl-2H-benzo[b][1,4]oxazines with benzoquinones

Organic & Biomolecular Chemistry, Journal Year: 2023, Volume and Issue: 22(5), P. 998 - 1009

Published: Dec. 26, 2023

An efficient Ru( ii )-catalyzed C–H activation-based spiroannulation of benzoxazines with easily available benzoquinone and N -sulfonyl quinone monoimine has been realized, providing a straightforward strategy to access NH-containing spiropyrans.

Language: Английский

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