Hydrazide‐Catalyzed Polyene Cyclization: Asymmetric Organocatalytic Synthesis of
<i>cis</i>
‐Decalins
作者:Samuel J. Plamondon、Josephine M. Warnica、Dainis Kaldre、James L. Gleason
DOI:10.1002/anie.201911952
日期:2020.1.2
Polyene cyclizations offer rapid entry into terpenoid ring systems. Although enantioselective cyclizations of (E)-polyenes to form trans-decalin ring systems are well precedented, highly enantioselective cyclizations of (Z)-polyenes to form the corresponding cis-decalins have not been reported. Here, we describe the first application of iminium catalysis to the initiation of polyene cyclizations. Ethyl
多烯环化可快速进入萜类环系统。尽管(E)-多烯对映选择性环化以形成反式十氢化萘环系统的先例是有先例的,但尚未报道(Z)-多烯形成相应的顺式十氢化萘的高对映选择性环化。在这里,我们描述了亚胺催化在多烯环化反应中的首次应用。1,2-二氮杂-1-羧酸乙酯催化带有烯类引发剂的多烯的环化反应。此外,手性双环酰肼催化(Z)-多烯底物的环化反应,形成对映体高达97:3 er的顺式十氢化萘。DFT计算表明,催化剂在双环化过程中会通过稳定正电荷来促进反应。