title: Room temperature syntheses of entirely diverse substituted β-fluorofurans.
abstract: Synthesis of highly substituted 3-fluorofurans is reported. The sequence began with preparation of tert-butyldimethylsilyl alk-1-en-3-yn-1-yl ethers from 1,4-disubstituted alk-3-yn-1-ones. Subsequent fluorination of alkenynyl silyl ethers with Selectfluor gave 2-fluoroalk-3-yn-1-ones in almost quantitative yield. Subsequent 5-endo-dig cyclizations using chlorotriphenylphosphine gold(I)/silver trifluoromethanesulfonate (5/5 mol%), N-bromo- or N-iodosuccinimide and gold(I) chloride/zinc bromide (5/20 mol%), all at room temperature, provided a facile method for the generation of substituted 3-fluoro-, 3-bromo-4-fluoro-, and 3-fluoro-4-iodofurans in good yields. Also, 2,2-difluoroalk-3-yn-1-ones were prepared by fluorination of alk-3-yn-1-ones under organocatalytic conditions. The structures of (Z)-tert-butyldimethylsilyl but-1-en-3-yn-1-yl ether, 3-bromo-4-fluorofuran, and 3-fluoro-4-(phenylethynyl)furan were confirmed by X-ray crystallography.
authors.affiliation: Department of Chemistry, Oakland University, 2200 N. Squirrel Rd, Rochester, MI 48309-4477, USA.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Kraig A
authors.initials: KA
authors.lastname: Wheeler
authors.forename: Roman
authors.initials: R
authors.lastname: Dembinski
mesh_terms: D002384:Catalysis; D003500:Cyclization; D017611:Fluorine Compounds / Q000138:chemical synthesis*; D005663:Furans / Q000138:chemical synthesis*; D007536:Isomerism; D008958:Models, Molecular; D015394:Molecular Structure; D013696:Temperature
chemical_list: D017611:Fluorine Compounds; D005663:Furans; C039281:furan