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

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(27), P. 18753 - 18770

Published: June 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.

Language: Английский

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Iron-Catalyzed Three-Component 1,2-Azidoalkylation of Conjugated Dienes via Activation of Aliphatic C‒H Bonds

Chemical Science, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 1, 2025

Azidoalkyation is an efficient strategy for the conversion of unsaturated precursors into nitrogen-containing structural motifs.

Language: Английский

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Recent Advances in Non-Precious Metal Catalysis

Organic Process Research & Development, Journal Year: 2022, Volume and Issue: 26(8), P. 2281 - 2310

Published: Aug. 2, 2022

This review provides a summary of recently published developments in the field nonprecious metal catalysis (NPMC) and highlights range synthetic applications captured research between July October 2021. is an installment series on this area briefing Ni, Cu, Fe, Co catalysis. There has been evident increase publications NPMC, which indicates widespread interest among laboratories academia industry development utilization catalytic these metals.

Language: Английский

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Regio- and Enantioselective Hydromethylation of 3-Pyrrolines and Glycals Enabled by Cobalt Catalysis

JACS Au, Journal Year: 2024, Volume and Issue: 4(6), P. 2312 - 2322

Published: June 11, 2024

Enantioenriched 3-methylpyrrolidine, with its unique chiral nitrogen-containing core skeleton, exists widely in various functional molecules, including natural products, bioactive compounds, and pharmaceuticals. Traditional methods for synthesizing these valuable methyl-substituted heterocycles often involve enzymatic processes or complex procedures auxiliaries, limiting the substrate scope efficiency. Efficient catalytic methylation, especially an enantioselective manner, has been a long-standing challenge chemical synthesis. Herein, we present novel approach remote stereoselective installation of methyl group onto N-heterocycles, leveraging CoH-catalyzed asymmetric hydromethylation strategy. By effectively combining commercial cobalt precursor modified bisoxazoline (BOX) ligand, variety easily accessible 3-pyrrolines can be converted to enantiopure 3-(isotopic labeling)methylpyrrolidine compounds outstanding enantioselectivity. This efficient protocol streamlines two-step synthesis enantioenriched which previously required up five six steps under harsh conditions expensive starting materials.

Language: Английский

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Copper‐Catalyzed Asymmetric Acylboration of 1,3‐Butadienylboronate with Acyl Fluorides

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(43)

Published: Sept. 15, 2023

Abstract We report herein a Cu‐catalyzed regio‐, diastereo‐ and enantioselective acylboration of 1,3‐butadienylboronate with acyl fluorides. Under the developed conditions, reactions provide ( Z )‐β,γ‐unsaturated ketones bearing an α‐tertiary stereocenter high ‐selectivity excellent enantioselectivities. While direct access to highly enantioenriched E ‐isomers was not successful, we showed that such molecules can be synthesized optical purities via Pd‐catalyzed alkene isomerization from corresponding ‐isomers. The orthogonal chemical reactivities functional groups embedded in ketone products allow for diverse chemoselective transformations, which provides valuable platform further derivatization.

Language: Английский

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