{"title":"Stereoselective reduction of menthone with sodium dithionite in the presence of β-cyclodextrin","authors":"Ramaswamy Ravichandran, Soundar Divakar","doi":"10.1016/0304-5102(94)00129-4","DOIUrl":null,"url":null,"abstract":"<div><p>The effect of β-cyclodextrin (BCD) and its methyl and polymer derivatives on the stereoselective reduction of menthone was studied. Modification of the yield and the proportion of epimeric alcohols formed were found to be the salient features of this reaction. Reduction of menthone in aqueous solution in presence of heptakis-2,6-di-<em>O</em>-methyl-β-cyclodextrin (DMBCD) remarkably enhanced the yield to 68% (from 10%) resulting in a menthol/neomenthol ratio of 1:2.5. Aqueous DMF (1:1) as the solvent increased the yield from 14.0% in water to 76% in the presence of BCD, the menthol/neomenthol ratio being 1:3.6. Under phase transfer condition, DMBCD in water—benzene mixture gave 82.0% yield along with a good stereoselectivity compared to 47.0% in the absence of a phase transfer catalyst.</p></div>","PeriodicalId":16567,"journal":{"name":"分子催化","volume":"93 3","pages":"Pages L247-L251"},"PeriodicalIF":0.0000,"publicationDate":"1994-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0304-5102(94)00129-4","citationCount":"6","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"分子催化","FirstCategoryId":"1089","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0304510294001294","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"Chemical Engineering","Score":null,"Total":0}
引用次数: 6
Abstract
The effect of β-cyclodextrin (BCD) and its methyl and polymer derivatives on the stereoselective reduction of menthone was studied. Modification of the yield and the proportion of epimeric alcohols formed were found to be the salient features of this reaction. Reduction of menthone in aqueous solution in presence of heptakis-2,6-di-O-methyl-β-cyclodextrin (DMBCD) remarkably enhanced the yield to 68% (from 10%) resulting in a menthol/neomenthol ratio of 1:2.5. Aqueous DMF (1:1) as the solvent increased the yield from 14.0% in water to 76% in the presence of BCD, the menthol/neomenthol ratio being 1:3.6. Under phase transfer condition, DMBCD in water—benzene mixture gave 82.0% yield along with a good stereoselectivity compared to 47.0% in the absence of a phase transfer catalyst.
研究了β-环糊精(BCD)及其甲基衍生物和聚合物衍生物对薄荷酮立体选择性还原反应的影响。研究发现，该反应的显著特征是产率和外旋醇比例的改变。在七甲基-2,6-二- o -甲基-β-环糊精(DMBCD)存在下，薄荷酮在水溶液中的还原率显著提高到68%(从10%)，使薄荷醇/薄荷醇的比例达到1:25 .5。水溶液DMF(1:1)作为溶剂，使收率从水中的14.0%提高到BCD存在下的76%，薄荷醇/薄荷醇比为1:6 .6。在相转移条件下，DMBCD在水-苯混合物中的产率为82.0%，具有良好的立体选择性，而在没有相转移催化剂的情况下，产率为47.0%。
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