Modular Synthesis of Tetrahydrofluorenones from 5-Alkylidene Meldrum's Acids

• Published in: Journal of organic chemistry Vol. 71; no. 26; pp. 9899 - 9902
• Main Authors: Fillion, Eric, Dumas, Aaron M, Hogg, Sylvia A
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 22.12.2006; Amer Chemical Soc
• Subjects: Alicyclic compounds, terpenoids, prostaglandins, steroids; Alkenes - chemistry; Chemistry; Chemistry, Organic; Condensed benzenic and aromatic compounds; Dioxanes - chemistry; Exact sciences and technology; Fluorenes - chemical synthesis; Fluorenes - chemistry; Molecular Structure; Organic chemistry; Physical Sciences; Preparations and properties; Science & Technology; Stereoisomerism; Terpenoids; DITERPENES; ROUTE; TAIWANIA-CRYPTOMERIOIDES; (+/-)-DICHROANAL-B; PRECURSOR; DIELS-ALDER REACTIONS; BARK; PYROLYTIC GENERATION; THUJA-STANDISHII; DERIVATIVES; Terpenoid; Catalytic reaction; Natural product; Diels Alder addition; Thermal reaction; Tricyclic compound; Friedel Crafts reaction; Diterpene; Aromatic compound; Ethyl ether; Chemical synthesis; Fluorene derivatives; Ethylenic compound
• ISSN: 0022-3263; 1520-6904
• DOI: 10.1021/jo0618876

The one-pot synthesis of tetrahydrofluorenones, the core 6-5-6 tricyclic structural motif found in norditerpenoid natural products, from alkylidene Meldrum's acids via thermal Diels−Alder/BF3·OEt2-catalyzed Friedel−Crafts acylation reactions is described. A series of tetrahydrofluorenones was assembled in good yields, and the Diels−Alder/Friedel−Crafts acylation protocol allowed modification of the substitution within the rings.