A Cu‐catalyzed enantioselective allylic alkylation using a γ‐butyrolactone‐derived silyl ketene acetal as a nucleophile is reported. Critical to the development of this work was the identification of a novel mono‐picolinamide ligand with the appropriate steric and electronic properties to afford the desired alkylation products in high yields and high levels of enantiomeric excess.
Abstract
Herein, we report a Cu‐catalyzed enantioselective allylic alkylation using a γ‐butyrolactone‐derived silyl ketene acetal. Critical to the development of this work was the identification of a novel mono‐picolinamide ligand with the appropriate steric and electronic properties to afford the desired products in high yield (up to 96 %) and high ee (up to 95 %). Aryl, aliphatic, and unsubstituted allylic chlorides bearing a broad range of functionality are well‐tolerated. Spectroscopic studies reveal that a CuI species is likely the active catalyst, and DFT calculations suggest ligand sterics play an important role in determining Cu coordination and thus catalyst geometry.
