Alkylidene Meldrum′s Acid as Acceptor‐Donor‐Acceptor with Azomethine Ylide for Organocatalytic Asymmetric (3+2) Cycloaddition/Annulation: Synthesis of Chromeno[4,3‐<i>b</i>]pyrrolidine
作者:Yan‐Cheng Liou、Yi‐Ru Chen、Ching‐Wen Hsu、Xuan‐Rui Huang、Heng‐Wei Wang、Wenwei Lin
DOI:10.1002/adsc.202300609
日期:2023.11.7
A quinine-derived thiourea-catalyzed enantioselective double annulation strategy using alkylidene Meldrum′s acid as an acceptor-donor-acceptor with salicylaldehyde-derived azomethine ylide is reported. The methodology is realized via a (3+2) cycloaddition/transesterification/decarboxylation sequence, giving chromeno[4,3-b]pyrrolidines within 15–420 minutes at room temperature in 51–97% yields with
报道了一种奎宁衍生的硫脲催化的对映选择性双环化策略,使用亚烷基 Meldrum 酸作为受体-供体-受体与水杨醛衍生的偶氮甲碱叶立德。该方法通过(3+2) 环加成/酯交换/脱羧序列实现,在室温下 15–420 分钟内得到色并[4,3- b ]吡咯烷,产率 51–97%,其中1 下的ee为 92–99% –10 mol% 催化剂负载量。根据对照实验,提出了一种合理的活化模型,通过催化剂和 Meldrum 酸基序之间的氢键相互作用实现优异的立体诱导。