An asymmetric synthesis of the core carbazole structure, 6-desprenyl-carquinostatin 3 and 6-descycloavandulyl-lavanduquinocin 3, toward a total synthesis of carquinostatin A (1) and lavanduquinocin (2), has been established. Lipase QLM (Meito) catalyzed enantioselective acetylation of the racemic alcohol 6 gave the (-)-acetate 7 and the (+)-alcohol 6 with high enantioselectivity. The absolute stereochemistry of the (-)- and (+)-alcohol 6 have been determined to be R- and S-configurations, respectively, by the advanced Mosher method. In the same manner, the (-)-acetate 13 and the (+)-alcohol 12 have been obtained from the racemic alcohol 12. The (R)-(-)-acetate 13, derived from the (R)-(-)-acetate 7, was the same as the (-)-acetate 13, which has been determined to be (R)-configuration. Oxidation of the (R)-(-)-acetate 13 followed by hydrolysis afforded (R)-(-)-6-desprenyl-carquinostatin [and (R)-(-)-6-descycloavandulyl-lavanduquinocin] 3. In addition, oxidation of the (S)-(+)-alcohol 12 provided (S)-(+)-3, which is the enantiomer of 6-desprenyl-carquinostatin A (R)-(-)-3.
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http://dx.doi.org/10.1248/cpb.55.1060 | DOI Listing |
Nat Commun
January 2025
Shenzhen Grubbs Institute and Department of Chemistry, Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen, Guangdong, China.
3-Amino boron dipyrromethenes (BODIPYs) are a versatile class of fluorophores widely utilized in live cell imaging, photodynamic therapy, and fluorescent materials science. Despite the growing demand for optically active BODIPYs, the synthesis of chiral 3-amino-BODIPYs, particularly the catalytic asymmetric version, remains a challenge. Herein, we report the synthesis of boron-stereogenic 3-amino-BODIPYs via a palladium-catalyzed desymmetric C-N cross-coupling of prochiral 3,5-dihalogen-BODIPYs.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry and Chemical Biology, Harvard University, Cambridge, Massachusetts 02138, United States.
Reported herein is the synthesis of a novel chiral dicarboxylic ligand for Mn(II) and the application of the Mn complex to the highly enantio- and position-selective epoxidation of C═C under mild conditions, even with polyolefinic substrates. A stereomechanistic basis for asymmetric induction is suggested.
View Article and Find Full Text PDFInt J Biol Macromol
January 2025
Key Laboratory of Organosilicon Chemistry and Materials Technology, Ministry of Education; College of Materials Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, Zhejiang 311121, China. Electronic address:
Keto reductases are crucial NAD(P)H-dependent enzymes used for the enantioselective synthesis of alcohols from prochiral ketones. Typically, the NADPH cofactor is regenerated through a second enzyme and/or substrate. However, photocatalytic cofactor regeneration using water as a sacrificial electron and hydrogen donor presents a promising alternative, albeit a challenging one.
View Article and Find Full Text PDFOrg Lett
January 2025
Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Shanghai Key Laboratory of New Drug Design, and School of Pharmacy, East China University of Science and Technology, Shanghai 200237, P. R. China.
The efficient construction of chiral aryl-containing organosilicon frameworks via catalytic enantioselective three-component silylarylation of alkenes remains a great challenge. Herein, a photoredox/nickel dual-catalytic asymmetric protocol has been disclosed by using a chiral biimidazoline (BiIM) as the ligand, silylboranes as the silyl radical precursors, aryl bromides as the coupling partners, and morpholine as the promoter. Remarkably, the reaction features mild and green conditions, high reaction efficiency, and excellent enantioselectivity, enabling the facile synthesis of valuable chiral tropic acid and sila-isoflavanone structures.
View Article and Find Full Text PDFOrg Lett
January 2025
Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061, United States.
Highly stereo- and enantioselective synthesis of δ-alkyl-substituted ()-homoallylic alcohols via asymmetric allylation is developed. In the presence of a chiral phosphoric acid catalyst, allylation of aldehydes with α-substituted allylboronates provides δ-alkyl-substituted homoallylic alcohols with excellent ()-selectivities and enantioselectivities.
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