The asymmetric total synthesis of pyranicin (1) is reported. The butenolide ring was constructed via an asymmetric alkylation/ring-closing metathesis strategy. The three stereocenters in the left-hand tetrahydropyran ring were installed by sequential chiral auxiliary-mediated aldol reactions. Closure of the tetrahydropyran and fusion of the alkyl backbone were affected via a sequential ring-closing metathesis-cross-metathesis strategy.
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http://dx.doi.org/10.1021/ol900814w | DOI Listing |
Angew Chem Int Ed Engl
January 2025
Kunming Institute of Botany Chinese Academy of Sciences, State Key Laboratory of Phytochemistry and Plant Resources in West China, Lanhei Road 132, Heilongtan, 650201, Kunming, CHINA.
Plant sesterterpenoids are an extremely rare family of natural products that generally possess novel chemical structures and diverse biological activities. Here, we report the discovery of an unprecedented group of minor plant sesterterpenoids, gracilisoids B-E (2-5), which feature two types of highly functionalized bicyclo[3.2.
View Article and Find Full Text PDFBr J Ophthalmol
January 2025
Department of Ophthalmology and Visual Sciences, Prince of Wales Hospital, Hong Kong, Hong Kong
Background: To report the presenting clinical, serological and treatment profiles of 1439 patients with thyroid eye disease (TED) from a tertiary centre in Hong Kong.
Study Populations: Consecutive patients with TED presented to the Thyroid Eye Clinic (TEC), the Chinese University of Hong Kong between 2014 and 2023.
Methods: Prospective cohort and masked review of medical records and orbital images.
J Org Chem
January 2025
State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000 Gansu, P. R. China.
The asymmetric total syntheses of sarglamides A, C, and E in concise and protecting group free fashion is disclosed. Key steps involve an -selective Diels-Alder reaction to construct the bicyclo[2.2.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Changchun Institute of Applied Chemistry Chinese Academy of Sciences: Chang Chun Institute of Applied Chemistry Chinese Academy of Sciences, Jilin Province Key Lab of Green Chemistry and Process, CHINA.
A modular approach was developed for the first catalytic asymmetric total syntheses of naturally occurring C30 terpene quinone methides and their non-natural stereoisomers, which feature the presence of an unprecedented spiro[4.4]nonane-containing 6-6-6-5-5-3 hexacyclic skeleton. Resting on a chiral phosphinamide-catalyzed enantioselective reduction of 2,2-disubstituted cyclohexane-1,3-dione, a concise route for the synthesis of enantioenriched 6-6 bicyclic fragment was developed.
View Article and Find Full Text PDFPLoS One
January 2025
Department of Occupational Therapy, School of Health Professions, Faculty of Medical and Health Sciences, Tel Aviv University, Tel Aviv, Israel.
Importance: To efficiently perform bimanual daily tasks, bimanual coordination is needed. Bimanual coordination is the interaction between an individual's hands, which may be impaired post-stroke, however clinical and functional assessments are lacking and research is limited.
Objectives: To develop a valid and reliable observation tool to assess bimanual coordination of individuals post-stroke.
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