Recent Advances in Furan Chemistry. Part I

This chapter presents the syntheses of the furan ring from monosaccharides, hydrofurans, 1, 4-dicarbonyl compounds, Feist–Benary synthesis, epoxides and glycols, alkynes, cumulenes. 1,3-dicarbonyl compounds can be converted into furans by methods other than the classical Feist–Benary method, the essential feature of which is alkylation by a haloketone or similar species. Because reduction plus elimination reactions may convert butenolides into furans, any butenolide synthesis can be a basis for a furan synthesis. The protonation of furan leads to polymerization because the ring can open to polyfunctional products or the protonated species can act as an electrophile and attack another furan molecule. Protons are easily detached from the furan nucleus, especially when some activating group is present. Even the carbonate ion catalyzes the deuteration of position 5 in 2-furoic acid salt. The reactions of furan with metals including lithium and potassium, copper, tin, mercury; and nonmetals including boron, silicon, phosphorus, and iodine are presented. The oxidation and reduction reactions of furan are also presented in the chapter.