A Chemoenzymatic, Preparative Synthesis of the Isomeric Forms ofp-Menth-1-en-9-ol: Application to the Synthesis of the Isomeric Forms of the Cooling Agent 1-Hydroxy-2,9-cineole
作者:Stefano Serra、Claudio Fuganti、Francesco G. Gatti
DOI:10.1002/ejoc.200701010
日期:2008.2
A preparative-scale synthesis of the four p-menth-1-en-9-ol isomers 2a–5a has been achieved by means of two chemoenzymatic processes. Both synthetic pathways start from the enantiomeric forms of limonene that are converted into p-mentha-1,8-dien-9-al isomers 12 and 15. The baker's yeast mediated reduction of the latter aldehydes afforded compounds 3a and 5a, respectively, with very high enantioselectivity
四种 p-menth-1-en-9-ol 异构体 2a-5a 的制备规模合成已通过两种化学酶促过程实现。两种合成途径都从柠檬烯的对映体形式开始,将其转化为 p-mentha-1,8-dien-9-al 异构体 12 和 15。面包酵母介导的后一种醛的还原分别提供了化合物 3a 和 5a,与非常高的对映选择性。此外,12 和 15 的化学还原分别得到对映纯的非对映异构体 2a/3a 和 4a/5a 的混合物。PPL(猪胰腺脂肪酶)介导后一种混合物的分辨率,然后对衍生物 2b-5b 进行分级结晶,从而获得对映异构和非对映异构纯醇 2a-5a。然后,化合物 2a-5a 已被用作制备凉味剂 1-羟基-2,9-桉树脑 (6-9) 的四种异构体的起始材料。(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)