171231-07-5Relevant academic research and scientific papers
Efficient and highly selective cyclization induced by Lewis acid to generate 2-hydroxyl-α-cyclogeraniol
Wang, Zi,Qi, Weiyi,Yan, Yixuan,Hu, Youhong,Song, Linhua
, p. 1932 - 1939 (2016/11/25)
A cyclization reaction of the hydroxyl-protected geraniol epoxide induced by the different Lewis acids to generate 2-hydroxyl-α-cyclogeraniol has been explored. Compared with the previous methods, this method enhances the production and selectivity of this reaction without the consumption of a large amount of solvent. Also, the coordination of the metal with two oxygen atoms of hydroxyl groups might be crucial for the reaction is first addressed.
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.
Straightforward enantioselective synthesis of both enantiomers of karahana lactone using a domino ring-closure sequence
Galano, Jean-Marie,Audran, Gérard,Monti, Honoré
, p. 7477 - 7481 (2007/10/03)
A straightforward enantioselective synthesis of both enantiomers of karahana lactone is described starting from enantiopure (R) or (S)-4-hydroxy-3-methyl-cyclohex-2-en-1-one. The key step of the sequence is an acid-induced domino reaction with three pathways running. Because of the first description of karahana lactone as a solid, the structure was secured by X-ray structural analysis. (C) 2000 Elsevier Science Ltd.
Taxol Total Synthesis: Preparation of a Chiral Ring A Moiety via Biomimetic Cyclization and Evaluation of a Tandem Nitrile Oxide Strategy for Rings B/C
Alcaraz, L.,Harnett, J. J.,Mioskowski, C.,Gall, T. Le,Shin, Dong-Soo,Falck, J. R.
, p. 7209 - 7214 (2007/10/03)
A fully functionalized taxol ring A moiety 7 was efficiently prepared via biomimetic cation-olefin cyclization of chiral geraniol epoxide 2b using SnCl4 in toluene.Fractional crystallization provided endo-3 (50percent yield from 2b) that was converted to aldehyde 5 by stereospecific epoxidation, secondary alcohol protection, and PCC oxidation.NaOMe-mediated ring opening secured enal 6.Addition of lithium dithianne to 6 at low temperature provided 7 as the sole product in good yield.A tandem nitrile oxide cycloaddition strategy for creating the remaining B/C carbocycles as well as key functionality present in both rings was validated, in part, by cyclization of 14 to tricyclic isoxazoline 15.
