Enantioselective Synthesis of
<i>cis</i>
‐2,
<scp>6‐Disubstituted</scp>
‐4‐methylene Tetrahydropyrans via Chromium Catalysis
<sup>†</sup>
作者:Jing Bai、Bin Chen、Guozhu Zhang
DOI:10.1002/cjoc.202000296
日期:2020.12
2‐(trimethylsilyl methyl)allylation and Prins cyclization. Commercially available (2‐(chloromethyl)allyl)trimethylsilane serves as the bifunctional linchpin to combine two aldehydes to assemble the 2,6‐disubstituted pyrans. A variety of functional groups are compatible under the mild reaction conditions. The synthetic utility of this methodology was demonstrated by the asymmetric synthesis of 16 examples of
通过两步序列获得了对映体富集的2,6-二取代的4-亚甲基四氢吡喃,该过程由高对映选择性的铬催化的羰基2-(三甲基甲硅烷基甲基)烯丙基化和Prins环化组成。市售的(2-(氯甲基)烯丙基)三甲基硅烷充当双功能键,将两个醛结合起来组装2,6-二取代的吡喃。在温和的反应条件下,各种官能团均相容。该方法的合成效用通过16个实例均丙醇和8个2,6-二取代4-亚甲基四氢吡喃的不对称合成得到了证明,其中包括一个高级中间体,该中间体可以通过已知方法转化为天然产物中心洛宾。