Efficient synthesis of furan-2-ylacetates, 7-(alkoxycarbonyl)benzofurans, and 7-(alkoxycarbonyl)-2,3-dihydrobenzofurans based on cyclization reactions of free and masked dianions: a "cyclization/dehydrogenation" strategy.
[reaction: see text] A variety of furan-2-ylacetates have been prepared by dehydrogenation of monocyclic 2-alkylidenetetrahydrofurans, which are readily available by cyclizations of open-chained 1,3-dicarbonyl dianions with 1-bromo-2-chloroethane. 5'H-[2,3']Bifuranyl-2'-ones are available based on sequential "cyclization/dehydrogenation" reactions of alpha-acetyl-gamma-butyrolactones. A variety of 7-(alkoxycarbonyl)benzofurans and 7-(alkoxycarbonyl)-2,3-dihydrobenzofurans were prepared by a cyclization/dehydrogenation strategy. These reactions rely on cyclizations of 2-oxocycloalkane-1-carboxylate-derived 1,3-dicarbonyl dianions ("free dianions") or 1,3-bis-silyl enol ethers ("masked dianions") with various 1,2-dielectrophiles.
Bellur
Esen
E
Institut für Chemie, Universität Rostock, Albert-Einstein-Str. 3a, 18059 Rostock, Germany.
Langer
Peter
P
D000838:Anions / Q000737:chemistry; D001572:Benzofurans / Q000138:chemical synthesis* / Q000737:chemistry; D002264:Carboxylic Acids / Q000737:chemistry*; D003500:Cyclization; D004980:Ethane / Q000031:analogs & derivatives / Q000737:chemistry; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D006846:Hydrocarbons, Halogenated / Q000737:chemistry; D006865:Hydrogenation; D015394:Molecular Structure; D013237:Stereoisomerism
D000838:Anions; D001572:Benzofurans; D002264:Carboxylic Acids; D005663:Furans; D006846:Hydrocarbons, Halogenated; C039590:1-bromo-2-chloroethane; D004980:Ethane; C060089:2-furoic acid