Asymmetric Multicomponent Polymerizations of Aromatic Amines, Aldehydes, and Alkynes Toward Chiral Poly(propargylamine)s and the Backbone Transformation

The construction of functional chiral polymers with newly built chiral centers from entire achiral monomers is charming but challenging in chiral material science. In this work, an asymmetric multicomponent polymerization (aMCP) of aromatic primary amines, aromatic aldehydes, and alkynes was developed with the catalysis of CuOTf-pybox complex to produce chiral poly(propargylamine)s. The supramolecular interactions between the CuOTf-pybox complex and the reactive species not only assisted the formation of a preorganized intermediate state to induce stereoselective reaction to produce chiral polymers but also reduced the reaction-activated energy to enable efficient A3-polycoupling at room temperature, affording chiral poly(propargylamine)s with high yields (up to 96%), high molecular weights (Mns up to 44 800 g/mol), significant circular dichroism signal, good solubility, and high thermal stability. Moreover, the unique chiral aromatic poly(propargylamine)s with remaining N–H moieties enabled complete conversion to a new group of chiral polyheterocycles, poly(thiazolidine-2-imine)s with elongated conjugation and enhanced fluorescence, realizing polymer backbone transformation through facile reaction with benzoyl isothiocyanate. The aMCP has provided an efficient and convenient approach for the construction of chiral polymers with diversified structures from simple achiral monomers and may accelerate the development of chiral polymer materials.