An Efficient, Palladium-Catalyzed, Enantioselective Synthesis of (2R)-3-Butene-1,2-Diol and Its Use in Highly Selective Heck Reactions

A robust and scalable procedure for the palladium-catalyzed dynamic kinetic asymmetric transformation of 3,4-epoxy-1-butene into (2R)-3-butene-1,2-diol with water as the cosolvent is reported. Examination of the effects of solvent and temperature led to the identification of conditions that permitted use of 0.025 mol % catalyst, providing (2R)-3-butene-1,2-diol in 84% isolated yield and 85% enantiomeric excess. Subsequent Heck reactions with a diverse range of coupling partners are described and the influence of their electronic nature on maintaining the enantiopurity of the diol is discussed.