Hydroaminoalkylation (HAA) is demonstrated
to be a promising postpolymerization
route to catalytically prepare amine-functionalized atactic polypropylene.
Using a recently reported tantalum catalyst supported by a N,O-chelating cyclic ureate ligand, vinyl-terminated
polypropylene (VTPP) is transformed into both aryl and alkyl secondary
amine-terminated polyolefins. Early transition-metal-catalyzed hydroaminoalkylation
avoids protection/deprotection protocols typically required for secondary
amine synthesis. This single-step reaction can be performed at multigram
scale with minimal solvent and is atom economic, thereby allowing
for optimized product isolation. Materials are characterized by multinuclear
NMR spectroscopy, IR spectroscopy, DSC, and TGA. The utility of the
reactive and unprotected amine terminus is highlighted by the installation
of a fluorescent end group and the assembly of a graft copolymer by
condensation of the secondary amine terminus with carboxylic acid
moieties.