Ferrocene phosphane–carbene ligands in Cu-catalyzed enantioselective 1,4-additions of Grignard reagents to α,β-unsaturated carbonyl compounds

• Ferrocenyl phosphane–carbene ligands are useful for Cu-catalyzed conjugate addition of Grignard reagents.
• Best Michael acceptors are 5,6-dihydro-2H-pyran-2-one and cyclohex-2-enone.
• The ligands are applicable also to domino conjugate addition followed by aldol or Mannich reaction.
• NMR shows coordination of copper with carbene and weak coordination with phosphorus.

Chiral ferrocene phosphane–carbenes are good ligands for the copper-catalyzed 1,4-addition of Grignard reagents to various Michael acceptors. The products were obtained in high enantiomeric purity (up to e.r. = 95:5) and excellent regioselectivity (r.r. = 99:1). These ligands are also useful for domino conjugate addition followed by enolate trapping with imine and aldehyde.

Chiral ferrocene phosphane–carbenes are useful in the copper-catalyzed 1,4-addition of Grignard reagents to cyclic α,β-unsaturated carbonyl compounds. The products were obtained in high enantiomeric purity (up to e.r. = 95:5) and excellent regioselectivity. These ligands are applicable also for domino conjugate addition followed by reaction with imine or aldehyde.Figure optionsDownload as PowerPoint slide