Anti-Markonikov reactions, 6 - Rhodium-catalyzed amination of vinylpyridines: Hydroamination versus oxidative amination

Cationic rhodium complexes catalyze the amination of 2- and 8-vinylpyridine with secondary amines. Depending on the substrate and the reaction conditi ons either oxidative amination to yield the corresponding enamines 1a-8a or hydroamination to give 2-aminoethylpyridines 1b-8b occurs. In all cases pr oducts with anti-Markovnikov regioselectivity are obtained. For mechanistic studies novel cationic complexes of rhodium(I)-containing cyclooctadiene a nd vinylpyridine 12 as well as complexes containing cyclooctadiene, vinylpy ridine, and morpholine 13 were prepared and characterized by NMR spectrosco py and X-ray diffraction analysis.