Heteropoly Compound Catalyzed Synthesis of Both Z ‐ and E ‐α,β‐Unsaturated Carbonyl Compounds

An EZ switch : The cationic species of the heteropoly compounds has a critical impact on the Z / E selectivity of the Meyer–Schuster rearrangement of propargyl alcohols (see scheme). The isolation of the thermodynamically unfavorable Z ‐α,β‐unsaturated carbonyl compounds is notable. The high Z  selectivities were obtained at a reaction temperature as high as 50 °C.