Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyotodaigaku-Katsura, Nishikyo, Kyoto 615-8510, Japan.
J Am Chem Soc. 2011 Oct 26;133(42):16711-3. doi: 10.1021/ja207322d. Epub 2011 Sep 28.
Oxacyclic structures such as tetrahydrofuran (THF) rings are commonly found in many bioactive compounds, and this has led to several efforts toward their stereoselective syntheses. However, the process of catalytic asymmetric cycloetherification for their straightforward synthesis has remained a challenge. In this study, we demonstrate a novel asymmetric synthesis method for THF via the catalytic cycloetherification of ε-hydroxy-α,β-unsaturated ketones mediated by cinchona-alkaloid-thiourea-based bifunctional organocatalysts. This catalytic process represents a highly practical cycloetherification method that provides excellent enantioselectivities, even with low catalyst loadings at ambient temperature.
氧杂环结构，如四氢呋喃（THF）环，在许多生物活性化合物中很常见，这促使人们对其进行了立体选择性合成的研究。然而，其直接合成的催化不对称环醚化反应仍然是一个挑战。在这项研究中，我们通过金鸡纳生物碱-硫脲双功能有机催化剂介导的ε-羟基-α,β-不饱和酮的催化环醚化反应，展示了一种合成 THF 的新型不对称合成方法。该催化过程代表了一种非常实用的环醚化方法，即使在环境温度下使用低催化剂负载量，也能提供优异的对映选择性。
