Cu-Catalyzed Asymmetric Conjugate Additions of Dialkyl- and Diarylzinc Reagents to Acyclic β-Silyl-α,β-unsaturated Ketones. Synthesis of Allylsilanes in High Diastereo- and Enantiomeric Purity

A readily available and simple (MW = 444.5 g/mol) valine-based chiral phosphine is used to promote highly efficient catalytic asymmetric conjugate additions of dialkyl- and diarylzinc reagents to acyclic beta-silyl-alpha,beta-unsaturated ketones. The catalytic asymmetric protocol allows access to versatile allylsilanes that bear a trisubstituted olefin in high diastereo- and enantiomeric purity.