Flow-Microreactor-Enabled Chemoselective Anionic Polymerization of Styrenes Bearing Alkoxysilyl Groups

We herein report the flow-microreactor-enabled anionic polymerization of styrenes bearing trialkoxysilyl substituents. Trialkoxysilyl-substituted styrenes are particularly attractive in the context of post-polymerization modification in polymer chemistry because they provide up to three potential functional groups per repeating unit. However, the high reactivity of alkoxysilyl groups has made them largely incompatible with anionic polymerization. In this study, we demonstrate that the anionic polymerization initiated by 2-phenylhexyl lithium (2PHLi) in a flow microreactor ensured chemoselective initiation and afforded poly(trialkoxysilylstyrene)s with narrow molecular weight distributions. The polymerization proceeded in a living manner, allowing the successful synthesis of block copolymers. Importantly, the retained trialkoxysilyl groups on the obtained polymers can be converted to a variety of silyl groups, thereby affording diverse silyl-substituted polystyrenes. These results establish trialkoxysilyl styrenes as powerful platforms for accessing silicon-containing polymers and highlight the versatility of flow microreactors in enabling chemoselective polymerization and functionalization.