benzofurans and 2-furoic-acid

[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.

Topics: Anions; Benzofurans; Carboxylic Acids; Cyclization; Ethane; Furans; Hydrocarbons, Halogenated; Hydrogenation; Molecular Structure; Stereoisomerism