Deciphering the chain propagation mechanism in regioselective polymerization via alkene difunctionalization

Abstract

The integration of transition-metal catalysis with alkene difunctionalization represents a transformative strategy for the synthesis of stereodefined poly[arylene α-(aryl)ethylene]s (PAAEs). In this study, we utilize comprehensive computational modeling to decode the regioselectivity and chain-propagation mechanisms that govern the assembly of these tailored, stereospecific architectures. By evaluating chain-end, monomer-initiated, and step-growth pathways, we provide a holistic view of the polymerization manifold. Our results, supported by Natural Bond Orbital (NBO) analysis and space-filling models, underscore the decisive role of donor–acceptor interactions and fragment overlap in stabilizing key transition states during chain propagation. Furthermore, ALMO-Energy Decomposition Analysis (ALMO-EDA) quantifies the steric and electronic factors that disfavor regio-reversed polymer formation. Finally, we elucidate the energetic landscape that prioritizes the difunctionalized product over the competitive Heck-type pathway, providing a definitive rationale for the observed high chemoselectivity.