Facile stereoselective synthesis of (E)-and (Z)-α-substituted cinnamates : Stereospecific dehydration reaction with 1 -ethyl -3 -(3 -dimethylaminopropyl )carbodiimide (EDC) and copper(II) chloride

Abstract A highly stereoselective method for the synthesis of ( E )- and ( Z )-α-substituted cinnamates in good yield has been achieved by dehydration reaction of anti - and syn -α-substituted-β-hydroxyphenylpropiolate using EDC. This facile method has been used to synthesize various ( E )- and ( Z )-α-substituted cinnamates and ( E )- and ( Z )-α-alkylidene-γ-butyrolactones. The reaction mechanism of this highly stereospecific dehydration using EDC can be elucidated by the ω-dimethylamino group of EDC, which is believed to facilitate the deprotonation step.