摘要
A synergistic Pd/Zn dual chiral catalyst system has been developed for the stereodivergent transformation of Morita–Baylis–Hillman(MBH)carbonates and unprotectedα-hydroxyketones to afford the corresponding allylation products(>50 examples).These products bearing vicinal stereocenters were obtained in high yields with excellent regio-/diastereo-/enantioselectivities.On cyclization in an acidic medium,the allylation products could transform to the corresponding acyl-functionalizedβ,γ-disubstitutedα-methylene-γ-butyrolactones(AMGBLs).All four stereoisomers of AMGBL were readily accessed using the same starting materials with full control of the stereochemistry of the contiguous stereogenic centers,simply by switching the chiral ligand combination for the Pd/Zn system.A nucleophilic site-divergent reactivity was observed for the allylation of primary and secondaryα-hydroxyketones,suggesting that distinct enolate intermediates might have prevailed in these reactions.
基金
the National Key R&D Program of China(grant nos.2023YFA1506700,2022YFA1503702,and 2021YFF0701602)
National Natural Science Foundation of China(NSFC,grant nos.22231011 and 22271303)
Shanghai Scientific and Technological Innovation Project,China(grant no.22JC1401000).
