ENANTIOSELECTIVE HORNER-WADSWORTH-EMMONS REACTION USING CHIRAL LITHIUM 2-AMINOALKOXIDES

Abstract

Chiral lithium 2-aminoalkoxides ((1R, 2S)-4) were applied as chiral bases for the enantioselective Horner-Wadsworth-Emmons reaction between achiral phosphonates (2) and 4-tert-butylcyclohexanone (1). A chiral olefin ((R)-3b) was obtained in up to 52% enantiomeric excess (ee). It is shown that the formation of the lithium aldolate intermediate is reversible and is not responsible for the asymmetric induction.