166022-33-9Relevant academic research and scientific papers
Preparation of (S)-γ-cyclogeraniol by lipase-catalyzed transesterification and synthesis of (+)-trixagol and (+)-luffarin-P
Fujii, Mikio,Morimoto, Yosuke,Ono, Machiko,Akita, Hiroyuki
, p. 160 - 166 (2015/12/04)
Lipase-catalyzed kinetic resolution of γ-cyclogeraniol by Candida antarctica lipase B yielded 23% of enantiomerically pure (S)-γ-cyclogeraniol. (+)-trixagol and (+)-luffarin-P were synthesized from the obtained (S)-γ-cyclogeraniol, and the absolute config
Lipase-mediated resolution of the hydroxy-cyclogeraniol isomers: application to the synthesis of the enantiomers of karahana lactone, karahana ether, crocusatin C and γ-cyclogeraniol
Serra, Stefano,Gatti, Francesco G.,Fuganti, Claudio
experimental part, p. 1319 - 1329 (2009/12/01)
A comprehensive study on the lipase PS-mediated resolution of different hydroxy-geraniol isomers is reported. A number of α-, β- and γ-isomers bearing a 2-, 3- or 4-hydroxy functional group were synthesised regioselectively and then submitted to the lipase-mediated kinetic acetylation. The latter experiments showed that the 2-hydroxy isomers 4, 5 and 14 (α, γ and β, respectively) as well as cis-3-hydroxy α-cyclogeraniol 7 and cis-4-hydroxy γ-cyclogeraniol 10 could be easily resolved by this procedure. The enantiomeric purity of the main part of these compounds was increased by recrystallisation and the enantiopure diols obtained were used as building blocks for the synthesis of the natural terpenoids karahana lactone, karahana ether and crocusatin C and for the preparation of the synthetic intermediate γ-cyclogeraniol. The absolute configurations of the enantiomers of the diols 7, 10, 14 and 19 were determined by chemical correlation with the known compounds 40, 41, 39 and 41, respectively.
Syntheses of the enantiomers of γ-cyclogeranic acid, γ-cyclocitral, and γ-damascone: Enantioselective protonation of enolates
Fehr,Galindo
, p. 539 - 552 (2007/10/02)
(R)- and (S)-γ-cyclogeranic acid ((R)- and (S)-9, resp.) were obtained by resolution of the racemate, and their absolute configurations determined by chemical correlation. The γ-acids (R)- and (S)-9 were converted into (R)- and (S)-methyl γ-cyclogeranate ((R)- and (S)-6, resp.), and (R)- and (S)-γ-damascone ((R)- and (S)-5, resp.). A more direct entry to (R)- and (S)-9 consisted in the enantioselective protonation of a thiol ester enolate with (-)- or (+)-N-isopropylephedrine ((-)- or (+)-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 enantioselective protonation of ketone enolate 29 with (-)-N- isopropylephedrine ((-)-20). Organoleptic evaluation demonstrated that the (S)-enantiomers of methyl γ-cyclogeranate and γ-damascone are markedly superior to their (R)-enantiomers.
