Precise control of single unit monomer radical addition with a bulky tertiary methacrylate monomer toward sequence-defined oligo- or poly(methacrylate)s via the iterative process
Iterative single unit monomer radical addition with a bulky tertiary methacrylate monomer, adamantyl and isopropyl pendant methacrylate (IPAMA), under ATRP conditions was studied in detail toward the syntheses of sequence-defined oligo- or poly(methacrylate)s in higher yields. The introduction of an activated ester for the alkyl halide or the adduct was effective in improving the accuracy of the single unit addition of IPAMA without forming unfavorable products. Thus, a cycle consisting of 4 steps, “radical addition”, “transformation”, “selective cleavage”, and “active esterification”, was established to realize the circumstances for effective single unit monomer addition and the iterative process along with pendant modification. The cycle was actually repeated to synthesize 2 units of adduct in high yield.