Enantioselective Conjugate Addition of Malononitriles to Enynes: A Stereodivergent Approach to Chiral Allenes

Abstract

Quinine‐catalyzed enantioselective conjugate addition of malononitrile derivatives to enynes enables stereodivergent synthesis of trisubstituted chiral allenes. The reaction proceeds under mild conditions with good to excellent yields and high enantiomeric purities for both diastereoisomers. Optimization revealed that solvent and temperature strongly influence reactivity and stereochemical outcome. A broad range of aromatic and aliphatic enynes, as well as α‐substituted malononitriles, are well tolerated. The method is amenable to scale‐up and allows efficient derivatization of the resulting allenes into enantioenriched pyrazoles and furans, providing versatile building blocks for asymmetric synthesis.