Chiral cyclopentadienyl Rh complexes efficiently catalyze enantioselective cyclopropanations of electron-deficient olefins with -enoxysuccinimides as the C1 unit. Excellent asymmetric inductions and high diastereoselectivities can be obtained for a wide range of substrate combinations. The reaction proceeds under mild conditions without precautions to exclude air and water. Moreover, the synthetic utility of the developed method is demonstrated by concise syntheses of members of the oxylipin natural products family and the KMO inhibitor UPF-648.
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http://dx.doi.org/10.1039/c8sc05702h | DOI Listing |
Angew Chem Int Ed Engl
January 2025
RIKEN, Organometallic Chemistry Laboratory, 2-1 Hirosawa, 351-0198, Wako, Saitama, JAPAN.
The enantioselective [3+2] annulation of readily accessible aldimines with alkynes via C-H activation is, in principle, a straightforward and atom-efficient route for synthesizing chiral 1-aminoindenes, which are important components in a wide array of natural products, bioactive molecules, and functional materials. However, such asymmetric transformation has remained undeveloped to date due to the lack of suitable chiral catalysts. Here, we report for the first time the enantioselective [3+2] annulation of aldimines with alkynes via C-H activation using chiral half-sandwich scandium catalysts.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
Laboratory of Asymmetric Catalysis and Synthesis, Institute of Chemical Sciences and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne 1015, Switzerland.
Chiral cyclopentadienyl (Cp) metal complexes are frequently used in asymmetric catalysis by virtue of their high reactivity and selectivity. Planar-chiral-only rhodium and iridium cyclopentadienyl complexes are particularly promising due to unrestricted chemical space for Cp ligand design while retaining structural simplicity. However, they are currently still niche because of a lack of efficient synthetic strategies that avoid lengthy chiral auxiliary routes or chiral preparatory HPLC resolution of the complexes.
View Article and Find Full Text PDFSci Adv
November 2024
Institute of Chemistry Frontier, School of Chemistry and Chemical Engineering, Shandong University, Qingdao 266237, China.
A pair of enantiomers is known to have different biological activities. Two catalysts with opposite chirality are nearly always required to deliver both enantiomeric products. In this work, chiral rhodium(III) cyclopentadienyl complexes are repurposed as efficient catalysts for enantiodivergent and atroposelective hydroamination of sterically hindered alkynes.
View Article and Find Full Text PDFChemphyschem
November 2024
Deutsches Elektronen-Synchrotron DESY, Notkestr. 85, 22607, Hamburg, Germany.
The molecular structure of a ferrocene derivative with adjacent centers of chirality, 1,1'-bis(tert-butylphosphino)ferrocene, has been examined in the gas phase using broadband microwave spectroscopy under the isolated and cold conditions of a supersonic jet. The diastereomers of 1,1'-bis(tert-butylphosphino)ferrocene can adopt homo- and hetero-chiral configurations, owing to the P-chiral substituents on the cyclopentadienyl rings. Moreover, the internal ring rotation of each diastereomer gives rise to four conformers with eclipsed ring arrangements, where the two tert-butylphosphino groups were separated by dihedral angles of approximately 72°, 144°, 216°, and 288° with respect to the two ring centers.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2024
Hunan Key Laboratory of Micro & Nano Materials Interface Science, College of Chemistry and Chemical Engineering, Central South University, Changsha, 410083, China.
The chirality of metal-organic cages holds enormous potential for novel applications in diverse fields, while it is relatively rare to employ such asymmetric units for the construction of noncentrosymmetric materials. Herein, by self-assembling the 4,4',4''-nitrilotribenzoic acid (HNBA) with bis(cyclopentadienyl)-zirconium dichloride (CpZrCl, Cp=η-CH) in different solvent conditions, we have obtained three hierarchical packing modes of metallo-tetrahedra with distinct spatial symmetry groups (designated as Zr-α, Zr-β, and Zr-γ). Among them, Zr-α employs a simple cubic arrangement and is a common centrosymmetric superstructure, which consists of a pair of equimolar metallo-tetrahedra enantiomers in its unit cell.
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