Mg(II)-Catalyzed Conjugate Addition of MeNO₂ to α′-Hydroxyenones

Significance

Using a Mg(II)/(cyclopropyl)inda­box catalyst system, non-enolizable α′-hydroxy-α,β-unsaturated ketones can undergo Michael addition under base-free conditions with nitromethane to afford γ-nitroketones in moderate to excellent yield and with good to excellent enantioselectivity. Under the same reaction conditions, Michael acceptors such as N-acryloyloxazolidinones and alkylidene malonate esters showed high conversion, but 0% ee. The main drawbacks of this method are long reaction times (3-11 days) and the need of a large excess of nucleophile (nitro­methane is used as solvent).