Catalytic Enantioselective Tautomerization of Isolated Enols

Significance

This paper describes a nice unique method involving enantioselective tautomerization and protonation of isolated enols. Using catalytic lithiated chiral amino alcohol (1), slow addition of the isolated enol followed by warming from -78 °C to -40 °C and subsequent quenching with 5% aqueous HCl afforded the desired ketone with good ee. A nonlinear effect was observed pointing to higher order mixed aggregates being responsible for the asymmetric induction.