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 trueM¯n of 23.8 kDa corresponding to a trueX¯n of 10 with one directional sequence‐control due to their consistent head‐to‐tail linkage.

Alkylation of N‐vinylpyrrolidone using lithium diisopropylamide and bis(2‐bromoethyl) ether was carried out to obtain 3‐(2‐(2‐bromoethoxy)ethyl)‐1‐vinyl‐2‐pyrrolidone (2). The derivative 2 represents a versatile starting molecule for further modification via nucleophilic displacement yielding, for example, the bicyclic 2‐vinyl‐8‐oxa‐2‐azaspiro[4.5]decan‐1‐one (4) or the ammonium salt 3‐diethoxy‐N,N′‐((dimethylbenzyl)ammonium bromide)‐1‐vinyl‐2‐pyrrolidone (10). Via free radical polymerization of 4 and 10, the corresponding homopolymers were obtained. Copolymerization of 4 and 10 with N,N′‐diethylacrylamide yielded water‐soluble materials. The thermosensitive solubility of copolymers poly[(2‐vinyl‐8‐oxa‐2‐azaspiro[4.5]decan‐1‐one)‐co‐(N,N′‐diethylacrylamide)] and poly[(3‐diethoxy‐N,N′‐((dimethylbenzyl)ammonium bromide)‐1‐vinyl‐2‐pyrrolidone)‐co‐(N‐vinylpyrrolidone)] in water was investigated. © 2015 Society of Chemical Industry