The first Diels-Alder based synthesis of (-)-kainic acid is described. Danishefsky's diene and a vinylogous malonate derived from 4-hydroxyproline combine under high pressure to afford a key bicyclic intermediate with virtually no loss of enantiopurity. This adduct can be converted into the natural product with complete stereocontrol. [reaction: see text].
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http://dx.doi.org/10.1021/ol062419l | DOI Listing |
J Pharm Biomed Anal
March 2025
Guang'an Men Hospital, China Academy of Chinese Medical Sciences, Beijing 100010, China. Electronic address:
Daidzin, as one of isoflavone glycosides, has been reported to have multiple activities with few absorbed into body. However, the metabolic behavior of daidzin by intestinal flora has not been researched, that this defect severely constrains its applications. In this study, daidzin and its metabolites were qualitatively and quantitatively analyzed by HPLC and ultra-high performance liquid chromatography coupled to high-resolution mass spectrometry (UHPLC-HRMS) in the fermentation system for daidzin and fecal bacteria.
View Article and Find Full Text PDFJ Org Chem
December 2024
Donostia International Physics Center, Paseo Manuel de Lardizabal 4, 20018 Donostia-San Sebastián, Spain.
Defying the common Diels-Alder reactivity, the thermal cycloaddition between butadiene and tetrafluoroethylene (TFE) yields exclusively a [2 + 2] cycloadduct via a stepwise diradical mechanism. Here, we study the possibility of reverting to the normal [4 + 2] reactivity in this reaction under high pressure. DFT calculations using the eXtreme Pressure Polarizable Continuum Model (XP-PCM) suggest a more negative activation volume for the concerted [4 + 2] mechanism than the stepwise [2 + 2] mechanism and predict a switch in periselectivity at 1.
View Article and Find Full Text PDFBiosci Biotechnol Biochem
September 2024
Department of Applied Chemistry, Faculty of Science and Engineering, Waseda University, Tokyo, Japan.
Total syntheses of borolithochromes H1, H2, I1, and I2, the red pigments isolated from fossils of Jurassic putative red alga Solenopora jurassica, have been achieved. The naphthoquinone possessing a chiral sec-butyl side chain has been synthesized from (S)-2-methylbutanol. The Diels-Alder reaction of the chiral naphthoquinone and the previously reported diene was followed by one pot S-methylation/intramolecular Corey-Chaykovsky reaction/epoxide rearrangement to provide the benzo[gh]tetraphene skeleton.
View Article and Find Full Text PDFChemistry
June 2024
Univ Rouen Normandie, INSA Rouen Normandie, CNRS, Normandie Univ, COBRA UMR 6014, INC3 M FR 3038, 76000, Rouen, France.
Dearomative Diels-Alder cycloadditions between nitroarenes and 2-trimethylsilyloxycyclohexadiene are carried out under high pressure at room temperature in the absence of any chemical promoter. Reactions are performed with different arenes, including the highly aromatic naphthalenes and quinolines. They lead to 3D-scaffolds with exquisite exo-diastereoselectivity.
View Article and Find Full Text PDFChem Commun (Camb)
February 2024
Department of Chemistry, University of Fribourg, Chemin du Musée 9, Fribourg 1700, Switzerland.
We report the synthesis of two-dimensional and three-dimensional porous polyphenylenes (2D/3D-pPPs) the Diels-Alder cycloaddition polymerization reaction. The resulting 2D and 3D-pPPs showed surface areas up to 1553 m g, pore volumes of 1.45 cm g and very high H uptake capacities of 7.
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