Asymmetric Syntheses of (Z)- or (E)-beta,?-Unsaturated Ketones via Silane-Controlled Enantiodivergent Catalysis

Cu-catalyzed highly stereoselective and enantiodivergent syntheses of (Z)- or (E)-beta,?-unsaturated ketones from 1,3-butadienyl silanes are developed. The nature of the silyl group of the dienes has a significant impact on the stereo- and enantioselectivity of the reactions. Under the developed catalytic systems, the reactions of acyl fluorides with phenyldiemthylsilyl-substituted 1,3-diene gave (Z)-beta,?-unsaturated ketones bearing an a-tertiary stereogenic center with excellent enantioselectivities and high Z-selectivities, where the reactions with triisopropylsilyl-substituted 1,3-butadiene formed (E)-beta,?-unsaturated ketones with high optical purities and excellent E-selectivities. The products generated from the reactions contain three functional groups with orthogonal chemical reactivities, which can undergo a variety of transformations to afford synthetically valuable intermediates.

Automated summary

Cu-catalyzed highly stereoselective and enantiodivergent syntheses of (Z)- or (E)-beta,?-unsaturated ketones from 1,3-butadienyl silanes are developed. The nature of the silyl group of the dienes has a significant impact on the stereo- and enantioselectivity of the reactions. The reactions result in the formation of (Z)-beta,?-unsaturated ketones with excellent enantioselectivities and high Z-selectivities or (E)-beta,?-unsaturated ketones with high optical purities and excellent E-selectivities, depending on the silyl group used.