A highly efficient asymmetric organocatalytic addition of 3-substituted oxindole to isatin-derived ketimine is reported with excellent stereocontrol (>99 : 1 dr, >99% ee) under mild conditions. This method provides access to the bisoxindole structure moiety with two vicinal quaternary stereogenic centers.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1039/c4ob01039f | DOI Listing |
J Org Chem
December 2024
College of Biotechnology and Pharmaceutical Engineering, State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, 30 Puzhu Rd S., Nanjing 211816, China.
An electrochemical reductive bimolecular cycloaddition of 2-arylideneindane-1,3-diones has been reported for the synthesis of spirocyclopentanole indane-1,3-diones bearing five contiguous stereocenters with vicinal tetrasubstituted stereocenters, especially involving a quaternary carbon center, in moderate to good yields and excellent diastereoselectivities. The present protocol features mild reaction conditions, no external chemical redox reagents, excellent atom economy, and gram-scale synthesis. In addition, a mechanistic investigation indicates that the reactions proceed through a radical pathway.
View Article and Find Full Text PDFChem Asian J
December 2024
IISER Bhopal: Indian Institute of Science Education and Research Bhopal, Chemistry, 462066, Bhopal, INDIA.
Natural product synthesis has been the prime focus for the development of new chemical transformations and the drug discovery. The dimeric and oligomeric hexahydropyrrolo[2,3-b]indole alkaloids represent a architecturally intriguing class of cyclotryptamine alkaloids. These alkaloids share contiguous stereogenic centers with vicinal all-carbon quaternary stereogenic centers.
View Article and Find Full Text PDFOrg Lett
December 2024
School of Pharmaceutical and Chemical Engineering & Institute for Advanced Studies, Taizhou University, Taizhou, 318000 Zhejiang, China.
We herein report a switchable coupling of acrylic acids with ethyl glyoxylate under ruthenium catalysis enabling the synthesis of diverse functionalized γ-butenolides. The carboxyl-directed vinylic C-H cleavage and dual nucleophilic addition to aldehyde are achieved to deliver hydroxymethylated butanolides under mild and oxidant-free conditions. Alternatively, a controlled and unprecedented tandem C-H cyclization/oxidative homocoupling reaction is realized by using silver salt as the oxidant to generate a range of dimeric butenolides bearing vicinal all-carbon quaternary centers.
View Article and Find Full Text PDFOrg Lett
December 2024
Department of Chemistry and Shenzhen Grubbs Institute and Guangdong Provincial Key Laboratory of Catalysis and Shenzhen Key Laboratory of Small Molecule Drug Discovery and Synthesis, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China.
Daphnimacropodines A-C are members of a small but structurally distinct subfamily of alkaloids. Their congested polycyclic skeletons, and two vicinal quaternary stereocenters, present significant synthetic challenges. This paper describes two stereoselective approaches to constructing the tricyclic core structures of daphnimacropodines, achieved through a straightforward Rh-catalyzed [4 + 3] cycloaddition using simple building blocks.
View Article and Find Full Text PDFJ Am Chem Soc
December 2024
State Key Laboratory of Chemical Oncogenomics, Institute of Biopharmaceutics and Health Engineering, Tsinghua Shenzhen International Graduate School, Shenzhen 518055, China.
The high percentage of sp-hybridized carbons and the presence of chiral carbon centers could contribute to increased molecular complexity, enhancing the likelihood of clinical success of drug candidates. Three-dimensional (3D) bridged motifs have recently garnered significant interest in medicinal chemistry. Bicyclo[2.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!