Enantiomerically pure (+)-Ambrein was synthesized from (+)-drimane-8,11-diol prepared via lipase catalyzed kinetic resolution, and easily prepared (+)-gamma-cyclogeraniol. (C) 1997 Elsevier Science Ltd.
Total Synthesis of (+)-Acanthodoral by the Use of a Pd-Catalyzed Metal-ene Reaction and a Nonreductive 5-<i>e</i><i>xo</i>-Acyl Radical Cyclization
作者:Liming Zhang、Masato Koreeda
DOI:10.1021/ol0363063
日期:2004.2.1
[reaction: see text] The first total synthesis of the antibiotic acanthodoral (1) has been achieved from 3-methyl-2-cyclohexen-1-one in 19 steps in 2.1% overall yield. The synthesis features the use of a Pd-ene reaction in the presence of CO to form the endocyclic alkene 8, a nonreductive acylradical cyclization reaction, and a ring contraction reaction by the Wolff rearrangement. (+)-Acanthodoral
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
Enantiomerically pure (+)-Ambrein was synthesized from (+)-drimane-8,11-diol prepared via lipase catalyzed kinetic resolution, and easily prepared (+)-gamma-cyclogeraniol. (C) 1997 Elsevier Science Ltd.