Main-chain polymers of chiral imidazolidinone were successfully synthesized by reaction of chiral imidazolidinone dimers with disulfonic acid. Chiral imidazolidinones were incorporated into the main-chain of the polymer by ionic bonding. These polymers could be used as polymeric chiral organocatalysts for asymmetric Diels-Alder reactions.
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http://dx.doi.org/10.1039/c2cc18115k | DOI Listing |
J Org Chem
January 2025
Department of Chemistry, The Citadel, 171 Moultrie Street, Charleston, South Carolina 29409, United States.
We have developed a simple and straightforward synthesis of chiral -imidazolidinone cyclohexenones, featuring six contiguous stereocenters, from feedstock chemicals such as aminophenols, α,β-unsaturated aldehydes, and α-amino acids. Remarkably, this one-pot multicomponent reaction exhibits exceptional diastereoselectivity (>20:1 dr) and relies solely on an amino acid precursor as the chiral source, avoiding the use of transition metals or additional organocatalysts. This reaction is efficient and scalable, enabling synthesis on a gram-scale.
View Article and Find Full Text PDFElectronically tuned -symmetric stereogenic-at-iron complexes, featuring strongly σ-donating 1,2,3-triazolin-5-ylidene mesoionic carbene (MIC) ligands, exhibit enhanced catalytic efficiency compared to conventional imidazol-2-ylidene analogs, as demonstrated in nitrene-mediated ring-closing C(sp)-H amidation reactions. Furthermore, a chiral pinene-derived pyridyl triazole ligand enables a highly diastereoselective synthesis of a non-racemic chiral iron catalyst, thereby controlling the absolute configuration at the metal center, as confirmed by NMR and X-ray crystallography. This pinene-modified stereogenic-at-iron MIC complex demonstrates high catalytic activity and a respectable asymmetric induction in the ring-closing C(sp)-H amination of -benzoyloxyurea, yielding 2-imidazolidinones with enantiomeric ratios of up to 92 : 8.
View Article and Find Full Text PDFJ Am Chem Soc
January 2024
School of Chemistry and Chemical Engineering, Frontiers Science Center for Transformative Molecules and State Key Laboratory of Metal Matrix Composites, Shanghai 200240, P. R. China.
Covalent organic frameworks (COFs) have undergone extensive research as heterogeneous catalysts for a wide range of significant reactions, but they have not yet been investigated in the realm of electrochemical asymmetric catalysis, despite their recognition as an economical and sustainable strategy for producing enantiopure compounds. Here, we report a mixed-linker strategy to design multicomponent two-dimensional (2D) chiral COFs with tunable layer stacking for highly enantioselective electrocatalysis. By crystallizing mixtures of triamines with and without the MacMillan imidazolidinone catalyst or aryl substituent (ethyl and isopropyl) and a dialdehyde derivative of thieno-[3,2-]thiophene, we synthesized and structurally characterized a series of three-component homochiral 2D COFs featuring either AA or ABC stacking.
View Article and Find Full Text PDFJ Org Chem
November 2023
School of Pharmaceutical Sciences, Liaocheng University, Liaocheng 252000, Shandong, P. R. China.
An EtN-catalyzed cascade [3 + 2]-annulation of β-oxo-acrylamides with cyclic -sulfonyl ketimines or sulfamate-derived imines is developed under mild reaction conditions, which provides a concise and efficient route to access valuable sultam- or sulfamidate-fused imidazolidinone derivatives in good to excellent yields (80-95% yields) with excellent diastereoselectivities (>20:1 drs). The current protocol features atom economy, a transition-metal-free process, and broad functional group tolerance. Moreover, the asymmetric variant of the [3 + 2]-cycloaddition reaction was achieved in the presence of diphenylethanediamine or quinine-based bifunctional squaramide organocatalysts and , giving the corresponding chiral polycyclic imidazolidinones in 68-90% yields with 25-94% ees and >20:1 drs in all cases.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2023
Key Laboratory of Precise Synthesis of Functional Molecules of Zhejiang Province, Department of Chemistry, School of Science, Westlake University, Institute of Natural Sciences, Westlake Institute for Advanced Study, No. 600 Dunyu Road, Hangzhou, 310024, Zhejiang Province, China.
Chirality correction, asymmetry, ring-chain tautomerism and hierarchical assemblies are fundamental phenomena in nature. They are geometrically related and may impact the biological roles of a protein or other supermolecules. It is challenging to study those behaviors within an artificial system due to the complexity of displaying these features.
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