This study investigated the catalytic behavior of NHC-X ligands (X = F, Cl, Br, I) in cycloaddition reactions, focusing on both mononuclear and binuclear pathways. Using NCI (noncovalent interaction), RDG (reduced density gradient), ELF (electron localization function), and LOL (localized orbital locus) computational analyses, the electronic interactions and stability of the ligands were examined. The results showed that NHC-Cl exhibited the least steric hindrance and strongest transition state stabilization, making it the most efficient catalyst. NHC-F also demonstrated strong stabilization, particularly in the binuclear pathway. In contrast, NHC-Br showed moderate efficiency, whereas NHC-I was the least effective owing to higher Gibbs free energy values and greater steric hindrance, especially in polar solvents such as water and acetonitrile. This study emphasizes the crucial role of solvent effects and thermodynamic factors in influencing the catalytic efficiency. These findings provide a framework for optimizing NHC-based catalysts for chemical transformations.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1039/d4dt02225d | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Aza-[4 + 2]-cycloaddition of benzocyclobutenones into isoquinolinone derivatives enabled by photoinduced regio-specific C-C bond cleavage.
Nat Commun
December 2024
Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, 610064, China.
The activation of C-C bond of benzocyclobutenones under mild reaction conditions remains a challenge. We herein report a photoinduced catalyst-free regio-specific C1-C8 bond cleavage of benzocyclobutenones, enabling the generation of versatile ortho-quinoid ketene methides for aza-[4 + 2]-cycloaddition with imines, which offers a facile route to isoquinolinone derivatives, including seven family members of protoberberine alkaloids, gusanlung A, B, D, 8-oxotetrahydroplamatine, tetrahydrothalifendine, tetrahydropalmatine, and xylopinine. Furthermore, the catalytic enantioselective version of this strategy is also realized by merging synergistic photocatalysis and chiral Lewis acid catalysis.
View Article and Find Full Text PDFThree-component diels-alder reaction through palladium carbene migratory insertion enabled dearomative C(sp)-H bond activation.
Nat Commun
December 2024
Key Laboratory of Chemical Biology and Traditional Chinese Medicine Research, Ministry of Education of China, Key Laboratory of the Assembly and Application of Organic Functional Molecules of Hunan Province, College of Chemistry and Chemical Engineering, Hunan Normal University, Changsha, Hunan, 410081, China.
Owning to the versatile nature in participation of Diels-Alder (D-A) reactions, the development of efficient approaches to generate active ortho-quinodimethanes (o-QDMs) has gained much attention. However, a catalytic method involving coupling of two readily accessible components to construct o-QDMs is lacking. Herein, we describe a palladium carbene migratory insertion enabled dearomative C(sp)-H activation to form active o-QDM species through the cross-coupling of N-tosylhydrazones with aryl halides.
View Article and Find Full Text PDFSteering acidic oxygen reduction selectivity of single-atom catalysts through the second sphere effect.
Nat Commun
December 2024
Center of Artificial Photosynthesis for Solar Fuels and Department of Chemistry, School of Science, Westlake University, Hangzhou, China.
Natural enzymes feature distinctive second spheres near their active sites, leading to exquisite catalytic reactivity. However, incumbent synthetic strategies offer limited versatility in functionalizing the second spheres of heterogeneous catalysts. Here, we prepare an enzyme-mimetic single Co-N atom catalyst with an elaborately configured pendant amine group in the second sphere via 1,3-dipolar cycloaddition, which switches the oxygen reduction reaction selectivity from the 4e to the 2e pathway under acidic conditions.
View Article and Find Full Text PDFCatalytic Asymmetric Desymmetrizing [4+2] Cycloaddition/Base-Mediated Oxidative Aromatization Sequence: Synthesis of Isobenzofuranone-Embedded Chiral Arenes.
Org Lett
December 2024
Department of Chemistry, Indian Institute of Technology Guwahati, North Guwahati, Assam 781039, India.
Herein, an organocatalytic asymmetric desymmetrizing [4+2] cycloaddition/base-mediated oxidative aromatization reaction sequence has been developed between spirophthalide 2,5-cyclohexadienones and β-methyl cinnamaldehydes. The reaction proceeds through chiral dienamine intermediate formation, and the densely functionalized spirocyclic isobenzofuranone-embedded chiral arenes were formed in high yields with excellent enantioselectivities. A 2-fold desymmetrization reaction was also performed, and the products were obtained in high enantioselectivities.
View Article and Find Full Text PDFSolvent Controlled Chemodivergent Sulfonyl Addition into Enynones: Synthesis of α-Furyl Sulfones and Stereodefined Vinyl Sulfones.
J Org Chem
December 2024
Department of Chemistry, National Institute of Technology, Tiruchirappalli 620015, Tamilnadu, India.
Sodium salt of aryl sulfinic acid reacts with enynone in a different manner, yielding α-furyl sulfone and stereodefined vinyl sulfone in toluene and EtOH respectively in the presence of ZnCl. The salient features of this protocol include chemoselectivity, broad substrate scope, high efficiency, high yield, and easy purification. The synthetic utilities of the products are demonstrated by cycloaddition and cis-trans photoisomerization reactions.
View Article and Find Full Text PDFWant 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!