A method for regioselective ring openings of 3,4- and 2,3-epoxy alcohols with ambident nitrogen heterocycles is described. Using a diarylborinic acid catalyst, a single regioisomer is favored in couplings of nucleophile and electrophile partners that display low regioselectivity under conventional conditions. The method provides access to aromatic heterocycles bearing stereochemically defined, functionalized alkyl substituents, a product class similar in structure to medicinally relevant compounds such as the acyclic nucleoside analogues.
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http://dx.doi.org/10.1021/acs.orglett.1c02412 | DOI Listing |
J Am Chem Soc
December 2024
State Key Laboratory of Chemical Biology, Shanghai Institute of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China.
Here, we report the enantioselective total syntheses of four diepoxy--kaurane diterpenoids including (-)-Macrocalin B, (-)-Acetyl-macrocalin B, and (-)-Isoadenolin A and the revised structure of (-)-Phyllostacin I, which hinges on the strategic design of a regioselective and stereospecific trapping of a highly reactive [3.2.1]-bridgehead enone intermediate via a tethered intramolecular Diels-Alder reaction.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Qingdao Institute of BioEnergy and Bioprocess Technology Chinese Academy of Sciences, Bio-based Materials, Songling Road 189., 266101, Qingdao, CHINA.
The poly(lactic-co-glycolic acid) (PLGA) with completely alternating sequence has attracted growing attention as an ideal candidate in controlled drug delivery. However, the approach to completely alternating PLGA remains a challenge. Herein, we report the successful synthesis of completely alternating PLGA via highly regioselective and stereoselective ring-opening polymerization.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
December 2024
Jinan University College of Pharmacy, College of Pharmacy, CHINA.
Highly functionalized xanthenes possess an impressive range of bioactivities and daunting synthetic challenge due to their unique ring systems and stereocenters. Here, we report an unprecedented ketyl radicals-induced skeletal rearrangement reaction of spirodihydrobenzofurans, enabled by zero-valent iron as reducing agents via photoredox catalysis, facilitating the facile preparation of various highly functionalized xanthenes. The features of this protocol include high chemo- and regioselectivity, exceptionally mild conditions, a broad substrate scope, scalability to gram-scale quantities, and consistent delivery of good to excellent yields.
View Article and Find Full Text PDFChem Commun (Camb)
December 2024
College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing 314001, Zhejiang, China.
This paper describes a ferric nitrene/photoredox dual-catalyzed anti-Markovnikov ring-opening of epoxides under neutral conditions for providing α-substituted acetophenones. A DFT-based calculation supported the reaction regioselectivity. The catalytic system could also be applied to the formation of C-O and C-N bonds nucleophilic functionalization of benzylic C-H bonds.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Chemistry, Dalian University of Technology, Dalian 116024, P. R. China.
An efficient palladium-catalyzed -allylic alkylation of pyrazoles and unactivated vinylcyclopropanes is demonstrated, affording various -alkyl pyrazoles in ≤99% yield. This protocol displays high atom economy, a broad range of substrates, and excellent regioselectivity and stereoselectivity. Late-stage modification of bioactive molecules, scaled-up reaction, and divergent derivatization documented the practicability of this methodology.
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