Elegant asymmetric synthesis of hasubanan alkaloids have been developed over the past decades. However, a divergent approach leading to all three sub-classes of this family of natural products remains unknown. We report herein the realization of such an endeavor by accomplishing enantioselective total syntheses of four representative members. The synthesis is characterized by catalytic enantioselective construction of the tricyclic compounds from which three different intramolecular C-N bond forming processes leading to three topologically different hasubanan alkaloids are developed. An aza-Michael addition is used for the construction of the aza-[4.4.3]-propellane structure of (-)-cepharamine, whereas an oxidation/double deprotection/intramolecular hemiaminal forming sequence is developed to forge the bridged 6/6/6/6 tetracycle of (-)-cepharatines A and C and a domino bromination/double deprotection/cyclization sequence allows the build-up of the 6/6/5/5 fused tetracyclic structure of (-)-sinoracutine.
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http://dx.doi.org/10.1038/s41467-020-20274-1 | DOI Listing |
ChemMedChem
June 2024
School of Traditional Chinese Materia Medica, Key Laboratory of Innovative Traditional Chinese Medicine for Major Chronic Diseases of Liaoning province, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang, 110016, P.R. China.
Hasubanan alkaloids represent a distinct class of alkaloids bearing a structural resemblance to morphine, predominantly found in herbals of the Stephania genus. Their intriguing molecular architecture and potential analgesic properties have captured the interest of medicinal chemists worldwide. This review meticulously examines the natural distribution, structural characteristics, biosynthetic pathways, synthetic methodologies, and biological activities of hasubanans.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
October 2023
Key Laboratory of Applied Surface and Colloid Chemistry & School of Chemistry and Chemical Engineering, Shaanxi Normal University, 620 West Chang'an Ave, Xi'an, 710119, China.
Herein, we report a concise and divergent synthesis of the complex hasubanan alkaloids metaphanine and oxoepistephamiersine from commercially available and inexpensive cyclohexanedione monoethylene acetal. Our synthesis features a palladium-catalyzed cascade cyclization reaction to set the tricyclic carbon framework of the desired molecules, a regioselective Baeyer-Villiger oxidation followed by a MeNH triggered skeletal reorganization cascade to construct the benzannulated aza[4.4.
View Article and Find Full Text PDFBioorg Chem
October 2023
School of Traditional Chinese Materia Medica, Key Laboratory of Innovative Traditional Chinese Medicine for Major Chronic Diseases of Liaoning Province, Key Laboratory for TCM Material Basis Study and Innovative Drug Development of Shenyang City, Shenyang Pharmaceutical University, Shenyang 110016, People's Republic of China. Electronic address:
H NMR-guided fractionation led to the isolation of 16 alkaloids from the alkaloidal extract of Stephania longa, including 11 new hasubanan alkaloids (1-11) and five known alkaloids (12-16). Interestingly, compounds 2 and 11 are typically considered protonated tertiary amine compounds, whereas compounds 1 and 10 are regarded as oxidized versions of the corresponding compounds. Their gross structures were determined through an extensive analysis of spectroscopic data (NMR (nuclear magnetic resonance) and HRESIMS (high resolution electrospray ionization mass spectroscopy)), and their absolute configurations were established by comparing their experimental and calculated electronic circular dichroism (ECD) spectra.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2023
Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, 3663 N Zhongshan Road, Shanghai, 200062, China.
We report herein the asymmetric total synthesis of periglaucines A-C, N,O-dimethyloxostephine and oxostephabenine. The key strategies used include: 1) a Rh -catalyzed regio- and diastereoselective Hayashi-Miyaura reaction to connect two necessary fragments; 2) an intramolecular photoenolization/Diels-Alder (PEDA) reaction to construct the highly functionalized tricyclic core skeleton bearing a quaternary center; 3) a bio-inspired intramolecular Michael addition and transannular acetalization to generate the aza[4.4.
View Article and Find Full Text PDFNat Prod Res
June 2022
Department of Pathogenic Biology and Immunology, School of Life Sciences and Biopharmaceuticals, Guangdong Pharmaceutical University, Guangzhou, P.R. China.
Three new hasubanan-type alkaloids, stephalonine Q (1), stephalonine R (2) and stephalonine S (3), together with four known alkaloids, isolonganone (4), eletefine (5), aurantiamide (6), N-cinnamoyltyramine (7), were isolated from the whole plant of . Their structures were identified by NMR, HR-ESI-MS, CD methods and x-ray crystallography, as well as by comparison with the literature data. All isolated compounds were evaluated for their antimicrobial activities against five bacteria .
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