Spontaneous Thiol‐Yne Click Polymerization of Aliphatic Thiols and Sulfonyl‐Activated Alkynes: A Facile Route to Z‐Stereoregular Poly(β‐thiolvinylsulfone)s

Thiol-yne click polymerization has emerged as an efficient strategy for the synthesis of functional polymers. However, catalyst-free and spontaneous thiol-yne polymerization of aliphatic thiols remains challenging because of their low ionization efficiency and poor reactivity toward conventional alkynes under ambient conditions. Herein, we report a robust and spontaneous polymerization strategy employing bis(ethynylsulfone)s monomers, in which the strongly electron-withdrawing sulfonyl group effectively activates the ethynyl groups toward nucleophilic addition by aliphatic dithiols. This transformation proceeds smoothly at room temperature without the need for catalysts or initiators, affording poly(β-thiolvinylsulfone)s (PTVSs) with high molecular weights (up to 97 300) and remarkable Z-stereoregularity (up to 97%) in excellent isolated yields (up to 97%). Density functional theory calculations support a Michael-type addition mechanism, in which sulfonyl-thiol interactions direct anti-Markovnikov addition with high Z-selectivity. This work establishes a facile, efficient, and broadly applicable synthetic platform for the construction of structurally well-defined sulfur-rich macromolecules.