Alkali Enolates of Unsymmetrical Ketones from Silyl Enol Ethers. Highly Regioselective Aldol Reactions Dependent on the Nature of the Cation

摘要

In conclusion, the choice of the appropriate metallic countercation leads to a highly regioselective control on the reaction site of the unsymmetrical ketones in the aldol reaction. Any mixture of regioisomeric silyl enol ethers can be used since a single aldol product is selectively obtained. The enolate can be condensed very efficiently on both aromatic and aliphatic aldehydes as well as on α, β -unsaturated aldehydes.