CONVENIENT SYNTHESIS OF 4-(2,2-DICHLOROETHENYL)-5,5-DIMETHYLTETRAHYDRO-2-FURANONE DERIVATIVES, A KEY INTERMEDIATE OF PERMETHRINIC ACID.

Article abstract of DOI:10.1246/bcsj.57.802

A key intermediate of 2-(2,2-dichloroethenyl)-3,3-dimethylcyclopropanecarboxylic acid, 3-alkoxycarbonyl-(or acyl)-4-(2,2-dichloroethenyl)-5,5-dimethyltetrahydro-2-furanone was prepared by the base-catalyzed condensation of 2-methyl-3,5,5-trichloro-4-penten-2-ol with acetate derivatives such as malonic esters, acetoacetic esters, and benzoylacetate. The reactivity of 3-acetyl-4-(2,2-dichloroethenyl)-5,5-dimethyltetrahydro-2-furanone to an excess amount of thionyl chloride in ethanol was also examined. An analog, -butyl-4-(2,2-dichloroethenyl)-3-ethoxycarbonyl-5-methyltetrahydro-2 -furanone was also prepared in 31% yield.