Reaction Pathways and Redox States in α‐Selective Cobalt‐Catalyzed Hydroborations of Alkynes
Clemens K. Blasius, Vladislav Vasilenko, Regina Matveeva, Hubert Wadepohl, Lutz H. Gade
Abstract
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.
Topics & Concepts
CobaltCatalysisHydroborationChemistryRegioselectivityCatalytic cycleMarkovnikov's ruleLigand (biochemistry)Pincer movementMedicinal chemistryRedoxAlkylHydridePolymer chemistryOrganic chemistryMetalReceptorBiochemistryOrganoboron and organosilicon chemistryCatalytic C–H Functionalization MethodsCatalytic Cross-Coupling Reactions