2-硝基苯并呋喃和α-芳基-α-异氰基乙酸酯的非对映和对映选择性脱芳香形式[3 + 2]环加成得到带有3 a ,8 b -二氢-1 H -苯并呋喃[2,3- c ]的三环化合物具有三个连续立体中心的吡咯框架。该反应是通过铜醚有机催化剂实现的。获得的反应产物具有几乎完全的非对映选择性,并且对于许多取代的2-硝基苯并呋喃和异氰乙酸酯具有优异的对映体过量。
Dienamineactivation wins against oxa‐1,4/1,4: By using nitrovinyl phenols and enals, aminocatalysis allows the asymmetricsynthesis of chromans and dihydrocoumarins bearing a CC double bond at the 3‐position (see scheme; TMS=trimethylsilyl). The new protocol takes advantage of the dienamine reactivity of the enal and avoids the known oxa‐Michael/Michael sequence.
Sulfur Ylide Initiated [4 + 1]/[4 + 2] Annulation Reactions: A One-Pot Approach to Dibenzofuran Acrylate Derivatives
作者:Jiaan Shao、Wenteng Chen、Zhimin Ying、Shuangrong Liu、Feng Luo、Lili Ou
DOI:10.1021/acs.orglett.9b02260
日期:2019.8.16
A one-pot approach has been developed for the synthesis of polysubstituted dibenzofuran acrylate derivatives from (E)-2-(2-nitrovinyl)phenols, sulfur ylides, and alkynes. This protocol was carried out under mild reaction condition without any precious catalysts in generally moderate to good yields. Additionally, a plausible mechanism for the transformation was proposed.