Stereodivergent α-Addition of Yne-allylic Esters by Z/E-Selective Catalysis for Multicomponent Reaction/Polymerization

The precise control of complicated regioselectivity of 1,3-enynes upon addition reaction has been a long-standing challenge in synthetic chemistry, even more pronounced when simultaneously striving to achieve both Z and E selectivity. A unique copper-catalyzed stereodivergent Z/E-selective α-addition of yne-allylic esters for multicomponent reaction and polymerization was developed. The esters’ leaving ability and steric hindrance effect of intermediates synergistically controlled the regioselectivity and stereoselectivity for synthesizing both (E, Z, E)- and (E, E, E)-dienylamidines in up to 94% yield with 48 examples involving uncommon vinyl ketenimine intermediate and vinyl alkylidene ketenimine intermediate, respectively. Such approach could be further applied to multicomponent polymerization for preparing 10 special polymers in up to 94% yield with Mn up to 17,900 g/mol.