An Approach to Catalytic Enantioselective Protonation of Prochiral Lithium Enolates

Abstract

Protonation of prochiral lithium enolates ( 4), prepared from racemic 2-substituted-1-tetralones ( 2) via their silyl enol ethers ( 3), with excess succinimide in the presence of lithium bromide and 0.2 equivalent of a chiral tetradentate amine ( (R)- 1) in toluene at −78 °C gave optically active 2 in up to 83% ee. © 1997 Elsevier Science Ltd.