Direct oxidative cyclization of (eta2:eta2-CH2=CHCH2C6H4CHO)Ni(PR3) to form the nickelacycle and drastic acceleration of the cyclization by the addition of Me3SiOTf were observed. (eta2-PhCHO)Ni(PCy3)2 also reacted with Me3SiOTf to give (eta1:eta1-Me3SiOCH(Ph))Ni(PCy3)OTf.
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http://dx.doi.org/10.1021/ja0460716 | DOI Listing |
Angew Chem Int Ed Engl
January 2025
University of Toronto, Dept. of Chemistry, 80 St. George Street, M5S 3H6, Toronto, CANADA.
A copper-catalyzed enantioselective synthesis of borylated 1-pyrrolines from γ,δ-unsaturated oxime esters is reported. Twenty-four novel 1-pyrroline derivatives are reported in yields ranging from 26% to 96% and enantioselectivities from 74.5:25.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur Campus, Kalyani, Nadia 741 246, West Bengal, India.
The first asymmetric total synthesis of the tetraterpenoid (+)-7,7'-bistaxodione () via a unique late-stage electrochemical oxidative dimerization of a diterpenoid quinone methide tumor Inhibitor (+)-taxodione () has been described. The naturally occurring monomer was synthesized from aromatic abietane diterpenoid, ferruginol (1e) . Further, an efficient convergent synthetic route toward the naturally occurring aromatic abietane terpenoids has been shown via a Lewis acid-mediated diastereoselective cationic epoxy-ene cyclization.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Department of Chemistry, Queen's University, Kingston, ON K7L 3N6, Canada.
Tambjamines are complex bipyrrole-containing natural products that possess promising bioactive properties. Although is known to produce both cyclic tambjamine MYP1 and the linear precursor (YP1), the biosynthetic machinery used to catalyze the site-selective oxidative carbocyclization at the unactivated 1° carbon of YP1 has remained unclear. Here, we demonstrate that a three-component Rieske system consisting of an oxygenase (TamC) and two redox partner proteins is responsible for this unprecedented activity on YP1 and potentially, a non-native substrate (BE-18591).
View Article and Find Full Text PDFChem Asian J
January 2025
Nanjing University, School of Chemistry and Chemical Engineering, CHINA.
A novel and efficient strategy for the direct synthesis of 3-arylthioquinoline derivatives via radical induced tandem cyclization of propargylamines with diaryl disulfides was developed. This protocol undergoes a cascade sulfuration/ cyclization/ oxidation/ aromatization pathway to afford the desired products in a broad substrate scope using readily available starting materials under mild conditions. Based on this strategy, we further modified 3-arylquinolines to obtain two novel deep blue fluorescent molecules, QLSCz and QLSTCz, with good optical properties through two-step synthesis by oxidation and electron donor modification.
View Article and Find Full Text PDFChem Asian J
January 2025
East China University of Science and Technology, Institute of Fine Chemicals, Meilong Road, 200237, Shanghai, CHINA.
Oxidation of thia-pentapyrrane S-P4 with terminal β-linked pyrrole and thiophene units in the presence of various metal ions has been found to afford distinct porphyrinoids. Specifically, N-confused thiasapphyrin (1), Cu(III) norrole (2), neo-confused phlorin (3), and p-benzinorrole (4) were obtained, when S-P4 was oxidized with p-chloranil in acetonitrile in the presence of Ni2+, Cu2+, Cd2+, and Co2+, respectively. The structures of 1-4 have been clearly elucidated by NMR spectroscopy, HRMS, and X-ray crystal diffraction (for 2-4).
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