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Regioregulated Syntheses of Poly(aminopyridine)s by Pd‐catalyzed Amination Reaction
Author(s) -
Kuwabara Junpei,
Mori Hironori,
Teratani Takuya,
Akita Munetaka,
Kanbara Takaki
Publication year - 2009
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.200900033
Subject(s) - amination , 2 aminopyridine , catalysis , chemistry , polymer chemistry , organic chemistry , combinatorial chemistry
Regioregulated poly(aminopyridine)s were synthesized by a Pd‐catalyzed CN coupling reaction. The polymerization using Pd(0) and a bulky monodentate phosphine ligand distinctively produced the para ‐linked and meta ‐linked poly(aminopyridine)s, without the need for a protection process. The regioregularity of the polymer was confirmed by 1 H NMR spectroscopy. Model reactions were studied to evaluate the possibility of crosslinkage in the polymer. A large difference in reactivity was observed between 5‐amino‐2‐bromopyridine and 2‐amino‐5‐bromopyridine, which should have afforded same product. Density functional theory (DFT) calculations indicated that electron densities of the Br‐bound carbon atom and the pyridine‐nitrogen atom determine the reactivity of the monomers.