Green Synthesis of Acid Esters from Furfural via Stobbe Condensation

Abstract

Solvent-free Stobbe condensation of furfural1with dimethyl succinate2under anhydrous conditions at room temperature using dry-solid potassium tertiary butoxide gave 3-carbomethoxy, 4-furyl-3-butenoic acid3, which upon methylation followed by Stobbe condensation reaction with different aldehydes and/or ketones under anhydrous conditions at room temperature afforded substituted carbomethoxy acids5a–f. These acid ester products were saponified to the corresponding dicarboxylic acids6a–fwhich are useful in the synthesis of photochromic fulgides.