A bifunctional iminophosphorane (BIMP)-catalyzed, enantioselective intramolecular oxa-Michael reaction of alcohols to tethered, low electrophilicity Michael acceptors is described. Improved reactivity over previous reports (1 day vs 7 days), excellent yields (up to 99%), and enantiomeric ratios (up to 99.5:0.5 er) are demonstrated. The broad reaction scope, enabled by catalyst modularity and tunability, includes substituted tetrahydrofurans (THFs) and tetrahydropyrans (THPs), oxaspirocycles, sugar and natural product derivatives, dihydro-(iso)-benzofurans, and iso-chromans. A state-of-the-art computational study revealed that the enantioselectivity originates from the presence of several favorable intermolecular hydrogen bonds between the BIMP catalyst and the substrate that induce stabilizing electrostatic and orbital interactions. The newly developed catalytic enantioselective approach was carried out on multigram scale, and multiple Michael adducts were further derivatized to an array of useful building blocks, providing access to enantioenriched biologically active molecules and natural products.
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http://dx.doi.org/10.1021/jacs.3c03182 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Shanghai Jiao Tong University, Frontiers Science Center for Transformative Molecules, 800 Dongchuan Road, 200240, Shanghai, CHINA.
Along with the renaissance of radical chemistry, the past decade has witnessed rapid development in radical-mediated rearrangement reactions. A wide diversity of radical approaches harnessing functional-group migration (FGM) have been devised to enhance both synthetic efficiency and molecular complexity. However, the application of FGM reactions to construct stereogenic centers remains underexplored owing to the inherent challenges of asymmetric radical reactions.
View Article and Find Full Text PDFChem Soc Rev
January 2025
Pingyuan Laboratory, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, 453007, Henan, P. R. China.
The use of olefins in the construction of cyclic compounds represents a powerful strategy for advancing the pharmaceutical industry. Photocycloaddition has attracted significant interest from chemists due to its ability to exploit simple and readily available olefins along with their reaction patterns under mild conditions. Moreover, the sustainable and versatile pathways for generating highly reactive intermediates can greatly enrich both substrate diversity and reaction patterns.
View Article and Find Full Text PDFACS Cent Sci
January 2025
Department of Chemistry, Zhejiang University, Hangzhou 310058, China.
Recently, nickel catalysts have garnered considerable attention for their efficacy and versatility in asymmetric catalysis, attributed to their distinctive properties. However, the use of cost-effective and sustainable divalent nickel catalysts in C-H activation/asymmetric alkene insertion poses significant challenges due to the intricate control of stereochemistry in the transformation of the tetracoordinate C-Ni(II) intermediate. Herein, we report a Ni(II)-catalyzed enantioselective C-H/N-H annulation with oxabicyclic alkenes.
View Article and Find Full Text PDFACS Cent Sci
January 2025
College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, China.
Multicomponent reactions (MCRs), highly sought-after methods to produce atom-, step-, and energy-economic organic syntheses, have been developed extensively. However, catalytic asymmetric MCRs, especially those involving radical species, remain largely unexplored owing to the difficulty in stereoselectively regulating the extraordinarily high reactivity of open-shell radical species. Herein, we report a conceptually novel catalytic asymmetric three-component radical cascade reaction of readily accessible glycine esters, α-bromo carbonyl compounds and 2-vinylcyclopropyl ketones via synergistic photoredox/Brønsted acid catalysis, in which three sequential C-C (σ/π/σ) bond-forming events occurred through a radical addition/ring-opening/radical-radical coupling protocol, affording an array of valuable enantioenriched unnatural α-amino acid derivatives bearing two contiguous stereogenic centers and an alkene moiety in moderate to good yield with high diastereoselectivity, excellent enantioselectivity and good -dominated geometry under mild reaction conditions.
View Article and Find Full Text PDFDalton Trans
January 2025
Chongqing Key Laboratory of Green Catalysis Materials and Technology, College of Chemistry, Chongqing Normal University, Chongqing 401331, China.
A deeper understanding of the mechanisms underlying transition metal-catalyzed transformation is crucial for developing innovative strategies to synthesize chiral organoselenium compounds. In this study, we developed and investigated a three-layer chirality relay model for the rhodium-catalyzed asymmetric hydroselenation of alkenes through density functional theory (DFT) calculations. In the back layer of this model, the four bulky substituents on the phosphorus atom of the bidentate chiral MeO-BIPHEP ligand were positioned on axial and equatorial bonds, thereby influencing the configuration of the middle layer.
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