Chiral ligand-controlled asymmetric conjugate addition of alpha-trimethylsilanylacetate to acyclic and cyclic enones

Enantioselective Conjugate Addition of a Lithium Ester Enolate Catalyzed by Chiral Lithium Amides

Mixed aggregates of chiral lithium amide and lithium ester enolate have been employed in the enantioselective conjugate addition on alpha,beta-unsaturated esters. Michael adducts were obtained in ee's up to 76% combining a lithium enolate and a chiral 3-aminopyrrolidine lithium amide. The sense of the induction was found to be determined by both the relative configuration of the stereogenic centers borne by the amide and the solvent in which the reaction was conducted. [reaction: see text]