School of Chemistry & Chemical Engineering, and Jiangsu Key Laboratory of Green Synthetic Chemistry for Functional Materials, Jiangsu Normal University , Xuzhou, 221116, China.
J Org Chem. 2016 Jun 17;81(12):5056-65. doi: 10.1021/acs.joc.6b00603. Epub 2016 Jun 1.
The first catalytic asymmetric construction of the biologically important hexahydrocoumarin scaffold has been established, which takes advantage of chiral thiourea-tertiary amine-catalyzed enantioselective transformations. Besides, this reaction also realized the first catalytic asymmetric [3 + 3] cyclization of 4-arylidene-2-aryloxazol-5(4H)-ones with cyclohexane-1,3-diones, which afforded structurally diverse 3-aminohexahydrocoumarin derivatives in excellent diastereoselectivities and high enantioselectivities (all >95:5 dr, up to 96:4 er). The investigation on the activation mode suggested that the chiral thiourea-tertiary amine catalyst simultaneously activated the two substrates via hydrogen-bonding interaction. Moreover, this reaction could be applied to a large scale synthesis of enantioenriched hexahydrocoumarin. This approach will not only provide an efficient method for the construction of the chiral hexahydrocoumarin scaffold but also enrich the research areas of asymmetric organocatalysis and catalytic enantioselective [3 + 3] cyclizations.
首次建立了利用手性硫脲-叔胺催化的对映选择性转化来构建生物重要的六氢香豆素骨架的催化不对称方法。此外,该反应还实现了 4-亚芳基-2-芳基恶唑-5(4H)-酮与环己烷-1,3-二酮的首例催化不对称[3+3]环化反应,以优异的非对映选择性和高对映选择性(全部>95:5 dr,最高可达 96:4 er)得到结构多样的 3-氨基六氢香豆素衍生物。对活化模式的研究表明,手性硫脲-叔胺催化剂通过氢键相互作用同时激活了两个底物。此外,该反应可用于对映富集的六氢香豆素的大规模合成。该方法不仅为手性六氢香豆素骨架的构建提供了一种有效方法,而且丰富了不对称有机催化和催化对映选择性[3+3]环化反应的研究领域。