Ketoester-Ene Reaction of Silyl Enol Ether to Construct Quaternary Carbons

Significance

The authors describe a highly enantioselective ketoester-ene reaction that generates optically active β-hydroxy silyl enol ethers containing tertiary alcohols. This is a very nice reaction because the product not only contains a chiral quaternary carbon, but also a useful silyl enol ether. A reasonable amount of α-ketoester substrates works well with this reaction. A SegPhos-Pd-Ag catalyst system is used with the silver’s likely role to generate the cationic palladium species.