Asymmetric Michael Addition of 2‑Acetyl Azaarenes to β‑CF₃‑β-(3-indolyl)nitroalkenes Catalyzed by a Cobalt(II)/(imidazoline-oxazoline) Complex

The first enantioselective Michael addition of 2-acetyl azaarenes to β-CF₃-β-(3-indolyl)­nitroalkenes has been successfully achieved in the presence of a Co­(II)/(imidazoline-oxazoline) complex as the catalyst. The reaction affords a series of CF₃- and 3-indole-containing adducts featuring a trifluoromethylated all-carbon quaternary stereocenter in good to excellent yields (up to 99%) and enantioselectivities (up to 96% ee). Furthermore, the functional groups in the adducts including CO, NO₂, and the azaarene provide a large variety of useful transformations, leading to the formation of valuable intermediates such as optically active secondary alcohol, pyrroline, ester, and pyrrolidinone which all contain a 3-substituted indole and a trifluoromethylated all-carbon quaternary stereocenter.