title: Selective radical addition with a designed heterobifunctional halide: a primary study toward sequence-controlled polymerization upon template effect.
abstract: A ruthenium(II)-catalyzed, highly selective, quantitative radical addition of an alkene, methacrylic acid (MAA), has been achieved by using a template halide (2) containing a built-in amine group as a recognition site for the carboxyl group of the substrate. The specific ionic binding of MAA by the amine template (1:1 molar ratio) led to preferential formation of the 1:1 MAA-2 adduct, whereas a similar halide without a template induced MAA oligomerization even in the presence of an externally added amine. A competitive radical addition of MAA versus its ester form [methyl methacrylate (MMA)] on the halide further demonstrated that the substrate selectivity [k'(MAA)/k'(MMA)] for 2 is enhanced more than 10 times by the intramolecular introduction of the template relative to the result for the nontemplate halide. These specificities are most likely triggered by the specific interaction (recognition) of the carboxyl group in MAA via the acid-selective template amine, which is implanted in the close vicinity of the radical addition site in 2. These results intimate possibility of control over the repeat-unit sequence in precision polymerization.
authors: Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
authors: Shohei
authors: S
authors: Ida
authors: Takaya
authors: T
authors: Terashima
authors: Makoto
authors: M
authors: Ouchi
authors: Mitsuo
authors: M
authors: Sawamoto
mesh_terms: D000588:Amines / Q000737:chemistry; D005609:Free Radicals / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry; D011108:Polymers / Q000138:chemical synthesis*; D012428:Ruthenium
chemical_list: D000588:Amines; D005609:Free Radicals; D008689:Methacrylates; D011108:Polymers; C008384:methacrylic acid; D012428:Ruthenium