Protection and polymerization of functional monomers, 22. Synthesis of well‐defined poly(4‐vinylbenzoic acid) by means of anionic living polymerization of N‐(4‐vinylbenzoyl)‐N′‐methylpiperazine, followed by deprotection

Anionic polymerizations of N ‐(4‐vinylbenzoyl)‐ N ′‐methylpiperazine ( 3a ) and N ‐(4‐vinylbenzoyl)morpholine ( 3b ) were carried out in tetrahydrofuran at −78°C with oligo(α‐methylstyryl)‐dilithium, ‐disodium, and ‐dipotassium. The polymerizations of both 3a and 3b proceeded quantitatively to give stable living polymers having predicted molecular weights and narrow molecular weight distributions. Novel block copolymers, poly( 3a )‐ block ‐polystyrene‐ block ‐poly( 3a ) and poly( 3b )‐ block ‐polystyrene‐ block ‐poly( 3b ), were synthesized by using these living polymerization systems. Under acidic conditions (6 N HCl in 1,4‐dioxane‐water), quantitative hydrolysis of the amide linkage of the poly( 3a ) was achieved to give a well‐defined poly(4‐vinyl‐benzoic acid).