Insights into the Cobalt-Catalyzed Three-Component Coupling of Mixed Aromatic Organozinc Species, Carbonyl Compounds or Imines and Michael Acceptors: Synthetic and Mechanistic Aspects

The first examples of cobalt-catalyzed multicomponent couplings of mixed aromatic arylzinc reagents with Michael acceptors and carbonyl compounds or imines is described. The reaction system employs a cobalt(II)-2,2′-bipyridine or a cobalt(II)-1,10-phenanthroline complex as a catalyst for both organozinc generation and subsequent multicomponent assembly by formal Michael addition/aldol coupling or Mannich reaction. This study brings new insights into the synthetic scope and mechanism of the reaction.