Syntheses of the Enantiomers of ?-Cyclogeranic Acid, ?-Cyclocitral, and ?-Damascone: Enantioselective protonation of enolates
作者:Charles Fehr、Jos� Galindo
DOI:10.1002/hlca.19950780303
日期:1995.5.10
thiol ester enolate with (−)- or (γ)-N-isopropylephedrine((−)- or (γ)-20) and subsequent hydrolysis of the (R)-and (S)-S-phenyl γ-thiocyclogeranate ((R)- and (S)-24, resp.; 97% ee). The esters (R)- and (S)-24 were also used as precursors of (R)- and (S)-γ-damascone ((R)- and (S)-5, resp.). Alternatively, (S)-5 (75% ee) was obtained by enantioselectiveprotonation of ketone enolate 29 with (−)-N-isopropylephedrine