Furans from 2-halocarbonyl compound

Although bromo derivatives have been used, the two most common ot-halocarbonyl compounds for this reaction are chloroacetaldehyde and chloroacetone. The dicarbonyl component is typically ethyl acetoacetate or one of its derivatives. A variety of bases including triethylamine and potassium hydroxide can promote the reaction however, the most popular base is pyridine. Conversion to the furan takes place either at room temperature or upon heating to 50°C with reaction times varying from four hours to five days and yields ranging from 30-86%. 

Synthesis of furans by base catalyzed condensation of an a-halocarbonyl compound with an enol, derived from a 1,3-dicarbonyl compound (see 1st edition). 

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