Organocatalytic Enantioselective 1,3-Difunctionalizations of Morita-Baylis-Hillman Carbonates.

The in-situ-generated zwitterionic allylic ylides between Morita-Baylis-Hillman carbonates from isatins and chiral tertiary amine catalysts underwent highly regioselective and enantioselective 1,3-oxo-ethynylation or 1,3-amino-sulfenylation reactions with silyl ethyny1-1,2-benziodoxo13(1H)-ones or N-(aryl or alkylthio)imides, respectively, giving densely functionalized products bearing a quaternary stereo genic center. An array of diversely structured scaffolds were efficiently constructed from the products, showing the synthetic versatility of the current catalytic strategy.