The Application of N-Protected 3-Vinylindoles in Chiral Phosphoric Acid-Catalyzed [3+2] Cyclization with 3-Indolylmethanols: Monoactivation of the Catalyst to Vinyliminium
作者:Tao Fan、Hong-Hao Zhang、Can Li、Yang Shen、Feng Shi
DOI:10.1002/adsc.201501175
日期:2016.6.16
A highly enantioselective [3+2] cyclization of 3‐vinylindoles with isatin‐derived 3‐indolylmethanols has been established in the presence of chiral phosphoric acid, which constructed the enantioenriched cyclopenta[b]indole scaffold linking a 3‐vinylindole moiety in generally good yields, considerable diastereoselectivities and high enantioselectivities (up to 93%, >95:5 dr, >99.5:0.5 er). More importantly
在存在手性磷酸的情况下,已建立了由靛红衍生的3-吲哚基甲醇对3-乙烯基吲哚的高度对映选择性[3 + 2]环化反应,该化合物构建了对映体富集的环戊达[ b ]吲哚骨架,该骨架通常将3-乙烯基吲哚部分连接起来。收率,相当的非对映选择性和高对映选择性(高达93%,> 95:5 dr,> 99.5:0.5 er)。更重要的是,该反应利用了N-保护的3-乙烯基吲哚作为有效的反应物,这在实现由3-吲哚基甲醇参与的对映选择性转化中,成功地将手性磷酸单活化成乙烯基亚胺时面临着挑战。此外,该协议还解决了用3-吲哚基甲醇实现3-乙烯基吲哚的高度对映选择性[3 + 2]环化的挑战,这将成为构建连接3-乙烯基吲哚的对映体富集的环戊达[ b ]吲哚支架的有用策略。部分。