Enantioface-differentiating protonation with chiral γ-hydroxyselenoxides

Article abstract of DOI:10.1016/S0957-4166(97)00423-0

Enantioface-differentiating protonation of a chiral metal enolates of α-alkylcarbonyl compounds 7 has been developed using chiral γ-hydroxyselenoxides 1 as a proton source. Reaction of zinc bromide enolates of 2-benzyl- and 2-n-propylcyclohexanones with (S(Se))-1e gave (S)-2-benzylcyclohexanone 7a and (R)-2-n-propylcyclohexanone 7c in high enantiomeric excess, respectively. Intramolecular hydrogen bonding of the selenoxide 1, chelation effects between 1 and metal enolate, and 2-exo-hydroxy-10-bornyl-framework could contribute to this asymmetric induction.