Enabling Directional Sequence‐Control via Step‐Growth Polymerization of Heterofunctionalized Precision Macromonomers

Abstract The synthesis of periodic copolymers with a regularly recurring sequence in one direction along the polymeric backbone is presented, applying a step‐growth polymerization of heterofunctionalized precision macromonomers derived from solid phase synthesis (SPS) via photoinduced thiol‐ene coupling (TEC). Heterofunctional macromonomers with monomer sequence‐control of the AB type present a terminal alkene and a terminal thiol group carrying a photolabile protecting group to avoid uncontrolled polymerization by self‐initiation. As protecting group, 3,4‐methylenebisoxy‐6‐nitrobenzyl is attached onto the thiol via its bromide derivative directly on solid support. The protected heterofunctionalized macromonomer is polymerized in a two‐step procedure, first cleaving the photolabile group and subsequent polymerization of the macromonomer via TEC, giving a high molecular weight polymer with of 23.8 kDa corresponding to a of 10 with one directional sequence‐control due to their consistent head‐to‐tail linkage.