Enantioselective [5 + 1] cycloaddition of sulfur ylides and vinylethylene carbonates via synergistic palladium/chiral phosphonic acid catalysis

An effective method for the synthesis of dihydropyrans through synergistic palladium and chiral phosphonic acid catalysis was reported. This protocol proceeded under mild reactions and provided dihydropyrans in up to 87% yield and up to 97% ee.