Highly Diastereo- and Enantioselective Synthesis of Tetrahydrobenzo[b]azocines via Palladium-Catalyzed [4 + 4] Cycloaddition
作者:Can Gao、Xunhua Wang、Jitian Liu、Xiaoxun Li
DOI:10.1021/acscatal.0c05515
日期:2021.3.5
The construction of N-heterocyclic eight-membered rings with good regio-, stereo-, and enantioselective control remains a formidable challenge in asymmetric catalysis. Herein, we report a palladium-catalyzed asymmetric [4 + 4] cycloaddition of anthranils with γ-methylidene-δ-valerolactones in the presence of Et3B, delivering highly functionalized tetrahydrobenzo[b]azocine derivatives in high efficiency
Catalyst-free cyclization of anthranils and cyclic amines: one-step synthesis of rutaecarpine
作者:Jian Li、Zheng-Bing Wang、Yue Xu、Xue-Chen Lu、Shang-Rong Zhu、Li Liu
DOI:10.1039/c9cc06160f
日期:——
An efficient synthesis of a variety of quinazolinone derivatives via a direct cyclization reaction between commercially available anthranils and cyclic amines is described. The developed transformation proceeds with the merits of high step- and atom-efficiency, a broad substrate scope, and good to excellent yields, without additional catalysts, and offers a practical way for the preparation of rutaecarpine
The inherently strained furan-fused cyclobutenes, in situ generated via cycloisomerizations of allenyl ketones bearing cyclopropyl moiety under gold catalysis, have been utilized as reactive building blocks toward cross cycloadditions. The [4 + 2] and [3 + 2] annulations of these species with benzo[c]isoxazoles and N-iminoquinazolinium ylides furnish various three-dimensional cyclobutane-bridged polyheterocycles
通过在金催化下通过带有环丙基部分的烯丙基酮的环异构化原位产生的固有应变的呋喃稠合的环丁烯已被用作朝向交叉环加成的反应性结构单元。这些物质与苯并[ c ]异恶唑和N-亚氨基喹唑啉鎓叶立德的[4 + 2]和[3 + 2]环以良好的收率提供各种三维环丁烷桥联的多杂环化合物。多种典型的电子不足的1,3-二烯,杂二烯和1,3-偶极子可以捕获呋喃稠合的环丁烯,从而提供多种多环结构。