Department of Chemistry, Zhejiang University, Hangzhou 310027, P. R. China.
J Org Chem. 2020 Sep 18;85(18):11766-11777. doi: 10.1021/acs.joc.0c01548. Epub 2020 Sep 4.
3-Diazoindolin-2-imines reacted with nitrones to furnish 2-iminoindolin-3-ones through a Au(I)-catalyzed cascade oxygen transfer/imine exchange process. The prepared 2-iminoindolin-3-ones could be further transformed into 2-alknyl-2,3-dihydroquinazolin-4(1)-ones through a Ag(I)-catalyzed reaction with terminal alkynes. A MeOH-triggered ring expansion mechanism involving cyclic iminium formation and nucleophilic addition is proposed for this novel alkynylation reaction. This two-step procedure provides a general and convenient approach to 2-alknyl-2,3-dihydroquinazolin-4(1)-ones, which are privileged structures in medicinal chemistry.
3-重氮吲哚啉-2-亚胺与硝酮反应，通过 Au(I)催化的级联氧转移/亚胺交换过程生成 2-亚氨基吲哚啉-3-酮。所制备的 2-亚氨基吲哚啉-3-酮可以通过与末端炔烃的 Ag(I)催化反应进一步转化为 2-炔基-2,3-二氢喹唑啉-4(1)-酮。提出了一种涉及环状亚氨基形成和亲核加成的 MeOH 触发的环扩张机制来解释这种新型炔基化反应。该两步法为 2-炔基-2,3-二氢喹唑啉-4(1)-酮提供了一种通用且方便的合成方法，该化合物是药物化学中具有优势结构的化合物。
