the orthoesters are prepared. can be hydrolyzed under acidic conditions to give 5-alkylidene-2(5H)-furanones . Reaction of 1,2-hydroxyketones and (2,2-diethoxyvinylidene)triphenyl-phosphorane (2) via Michael addition and Wittig reaction yields orthoesters , which can be hydrolyzed to give 2(5H)-furanones and 2-ethoxyfurans respectively.