Asymmetric Syntheses of (<i>Z</i>)- or (<i>E</i>)-β,γ-Unsaturated Ketones via Silane-Controlled Enantiodivergent Catalysis
Jiaming Liu, Shang Gao, Evangelos Miliordos, Ming Chen
Abstract
Cu-catalyzed highly stereoselective and enantiodivergent syntheses of ( Z )- or ( E )-β,γ-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 )-β,γ-unsaturated ketones bearing an α-tertiary stereogenic center with excellent enantioselectivities and high Z -selectivities, where the reactions with triisopropylsilyl-substituted 1,3-butadiene formed ( E )-β,γ-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.