Stereoselective Synthesis of Multisubstituted Cyclohexanes by Reaction of Conjugated Enynones with Malononitrile in the Presence of LDA.

Molecules

Department of Organic Chemistry, Institute of Chemistry, Saint Petersburg State University, Universitetskaya nab., 7/9, 199034 Saint Petersburg, Russia.

Published: December 2020

Reaction of linear conjugated enynones, 1,5-diarylpent-2-en-4-yn-1-ones, with malononitrile in the presence of lithium diisopropylamide LDA, as a base, in THF at room temperature for 3-7 h resulted in the formation of the product of dimerization, multisubstituted polyfunctional cyclohexanes, 4-aryl-2,6-bis(arylethynyl)-3-(aryloxomethyl)-4-hydroxycyclohexane-1,1-dicarbonitriles, in yields up to 60%. Varying the reaction conditions by decreasing time and temperature and changing the ratio of starting compounds (enynone and malononitrile) allowed isolating some intermediate compounds, which confirmed a plausible reaction mechanism. The relative stability of possible stereoisomers of such cyclohexanes was estimated by quantum chemical calculations (DFT method). The obtained cyclohexanes were found to possess photoluminescent properties.

Download full-text PDF

Source
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7765106PMC
http://dx.doi.org/10.3390/molecules25245920DOI Listing

Publication Analysis

Top Keywords

conjugated enynones
8
malononitrile presence
8
stereoselective synthesis
4
synthesis multisubstituted
4
cyclohexanes
4
multisubstituted cyclohexanes
4
reaction
4
cyclohexanes reaction
4
reaction conjugated
4
enynones malononitrile
4

Similar Publications

Copper-Catalyzed Synthesis of Furan-Tethered Benzocyclobutenes via Carbene-Mediated 1,4-Sulfinate Migration-Annulation.

Org Lett

July 2024

School of Chemistry and Chemical Engineering, Zhejiang Sci-Tech University, Xiasha West Higher Education District, Hangzhou 310018, China.

A copper-catalyzed intramolecular cascade reaction of conjugated enynones has been achieved via a pivotal 1,4-sulfinate migration step. This process leverages a cost-effective and ecofriendly copper salt as catalyst, enabling the efficient construction of five- and four-membered rings in a rapid, sequential manner, producing furan-tethered benzocyclobutenes in good to excellent yields under mild conditions. The reaction is characterized by 100% atom economy, outstanding efficiency, and excellent diastereoselectivity in the cases studied.

View Article and Find Full Text PDF

Photoredox-Catalyzed 1,4-Peroxidation-Sulfonylation of Enynones: A Three-Component Radical Coupling Approach for the Synthesis of Highly Functionalized Allenes.

Org Lett

April 2024

Center for Metareceptome Research, Graduate School of Pharmaceutical Sciences, Chung-Ang University, 84 Heukseok-ro, Dongjak, Seoul, 06974, Republic of Korea.

An Eosin Y-catalyzed visible light-promoted 1,4-peroxidation-sulfonylation of enynones was achieved to give tetrasubstituted allenes. The photoredox catalysis of Eosin Y allowed the concomitant formation of peroxy and sulfonyl radicals, where the preferential peroxy radical addition to the alkene moiety of enynones resulted in the subsequent α-keto radical-sulfonyl radical cross couplings. The developed photoredox catalysis of Eosin Y demonstrates a regioselective 1,4-diradical addition strategy, opening up a new possibility of diradical functionalization of conjugate systems.

View Article and Find Full Text PDF

Inhibition of quorum sensing by chemical induction of the MexEF-oprN efflux pump.

Antimicrob Agents Chemother

February 2024

Department of Immunology and Microbiology, Costerton Biofilm Center, University of Copenhagen, Copenhagen, Denmark.

The cell-to-cell communication system quorum sensing (QS), used by various pathogenic bacteria to synchronize gene expression and increase host invasion potentials, is studied as a potential target for persistent infection control. To search for novel molecules targeting the QS system in the Gram-negative opportunistic pathogen , a chemical library consisting of 3,280 small compounds from LifeArc was screened. A series of 10 conjugated phenones that have not previously been reported to target bacteria were identified as inhibitors of QS in .

View Article and Find Full Text PDF

A General Synthesis of Cross-Conjugated Enynones through Pd Catalyzed Sonogashira Coupling with Triazine Esters.

Molecules

May 2023

Key Laboratory of Applied Surface and Colloid Chemistry (MOE), Xi'an Key Laboratory of Organometallic Material Chemistry, School of Chemistry and Chemical Engineering, Shaanxi Normal University, Xi'an 710119, China.

Article Synopsis
  • The palladium-catalyzed Sonogashira coupling provides a method for synthesizing cross-conjugated enynones from α, β-unsaturated acid derivatives, although direct conversions to cross-conjugated ketones are rare due to the vulnerability of C-C bonds near carbonyl groups.
  • This study introduces a selective C-O activation method utilizing α, β-unsaturated triazine esters as acyl electrophiles, allowing for efficient cross-coupling without the use of bases or phosphine ligands.
  • The approach successfully produced 31 different cross-conjugated enynones, showcasing the effectiveness of triazine-mediated C-O activation in creating highly functionalized ketones.
View Article and Find Full Text PDF

Catalytic Radical-Triggered Annulation/Iododifluoromethylation of Enynones for the Stereospecific Synthesis of 1-Indenones.

J Org Chem

July 2023

School of Pharmacy, Continuous Flow Engineering Laboratory of National Petroleum and Chemical Industry, Changzhou University, Changzhou, Jiangsu 213164, China.

A new Pd(II)-catalyzed annulation/iododifluoromethylation of enynones has been developed for the synthesis of versatile 1-indanones with moderate to good yields (26 examples). The present strategy enabled the concomitant incorporation of two important difluoroalkyl and iodo functionalities into 1-indenone skeletons with ()-stereoselectivity. The mechanistic pathway was proposed, consisting of the difluoroalkyl radical-triggered α,β-conjugated addition/5--dig cyclization/metal radical cross-coupling/reductive elimination cascade.

View Article and Find Full Text PDF

Want AI Summaries of new PubMed Abstracts delivered to your In-box?

Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!