Herein we describe concise enantioselective chemical syntheses of (-)-viridin and (-)-viridiol. Our convergent approach couples two achiral fragments of similar complexity and employs an enantioselective intramolecular Heck reaction to set the absolute stereochemical configuration of an all-carbon quaternary stereocenter. To complete the syntheses of these base- and nucleophile-sensitive natural products, we conduct carefully orchestrated site- and diastereoselective oxidations and other transformations. Our work is the first to generate these targets as single enantiomers.
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http://dx.doi.org/10.1021/jacs.7b02829 | DOI Listing |
Org Lett
January 2025
State Key Laboratory of Antiviral Drugs, Pingyuan Laboratory, Key Laboratory of Green Chemical Media and Reactions, Ministry of Education, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Highly asymmetric (3+3) annulation of diaziridines with oxiranes via C-N bond cleavage in diaziridine was achieved under 10 mol % of chiral copper(II) complex as the catalyst under mild reaction conditions. With Cu(OTf) as the Lewis acid and C-symmetric imidazolidine-pyrroloimidazolone pyridine as the ligand, diverse tetrahydro-[1,3,4]-oxadiazines were obtained by stereospecific C-N/C-O bond formation in moderate to good yields (up to 93% yield) and high diastereo- (>20:1 dr) and enantioselectivities (up to 92% ee). The catalytic cycle and stereochemical model were proposed by DFT calculation.
View Article and Find Full Text PDFJ Org Chem
January 2025
State Key Laboratory of Fine Chemicals, Department of Pharmaceutical Engineering, School of Chemical Engineering, Dalian University of Technology, 2 Linggong Road, Dalian 116024, China.
This paper presents a new strategy for the construction of the chiral 4-chromene skeleton. A series of chiral 2-trifluoromethyl-4-(indol-3-yl)-4-chromenes were synthesized in moderate to good yields (60-92%) with excellent enantioselectivity (up to 97% ee) through the palladium-catalyzed asymmetric condensation of 2-chromenes and indoles. These trifluoromethylated, stereochemically rich building blocks hold potential value in medicinal chemistry.
View Article and Find Full Text PDFNat Commun
January 2025
State Key Laboratory of Organometallic Chemistry, Shanghai of Organic Chemistry, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Shanghai, PR China.
Motivated by the inherent benefits of synergistically combining electrochemical methodologies with nickel catalysis, we present here a Ni-catalyzed enantioselective electroreductive cross-coupling of benzyl chlorides with aryl halides, yielding chiral 1,1-diaryl compounds with good to excellent enantioselectivity. This catalytic reaction can not only be applied to aryl chlorides/bromides, which are challenging to access by other means, but also to benzyl chlorides containing silicon groups. Additionally, the absence of a sacrificial anode lays a foundation for scalability.
View Article and Find Full Text PDFOrg Lett
January 2025
School of Chemistry and Chemical Engineering, Qufu Normal University, Qufu, Shandong 273165, China.
The enantioselective ring-opening reactions of methylenecyclopropanes (MCPs) involving C-C bond activation via oxidative addition of transition metals have been rarely reported. Here, we disclose a Pd/Cu-catalyzed enantio- and regioselective coupling between cyclic imino esters and MCPs to produce α-allylated 2-pyrrole derivatives. In this reaction, azomethine ylide formed by a chiral copper catalyst with ketimine ester would serve as a nucleophile to react with activated MCPs via palladium catalysis.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen 518132, China.
The absolute and relative configurations of bioactive chiral molecules are typically relevant to their biological properties. It is thus highly important and desirable to construct all possible stereoisomers of a lead candidate or a given bioactive natural compound. Synergistic dual catalysis has been recognized as a reliable synthetic strategy for a variety of predictable stereodivergent transformations.
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