Reaction Pathways and Redox States in α-Selective Cobalt-Catalyzed Hydroborations of Alkynes.
Cobalt(II) alkyl complexes supported by a monoanionic NNN pincer ligand are pre-catalysts for the regioselective hydroboration of terminal alkynes, yielding the Markovnikov products with α:β-(E) ratios of up to 97:3. A cobalt(II) hydride and a cobalt(II) vinyl complex appear to determine the main reaction pathway. In a background reaction the highly reactive hydrido species specifically converts to a coordinatively unsaturated cobalt(I) complex which was found to re-enter the main catalytic cycle.
['Blasius|Clemens K|CK|', 'Vasilenko|Vladislav|V|', 'Matveeva|Regina|R|', 'Wadepohl|Hubert|H|', 'Gade|Lutz H|LH|http://orcid.org/0000-0002-7107-8169']
alkynes pincer ligand T-shaped complex alkenyl boronates cobalt