An Yb(OTf)(3)and visible light relay catalyzed [3+2] cycloaddition/[3,3]-rearrangement/[4+2] cycloaddition in one pot to prepare oxazonine-fused endoperoxides
An Yb(OTf)(3)and visible light relay catalyzed [3+2] cycloaddition/[3,3]-rearrangement/[4+2] cycloaddition in one pot to prepare oxazonine-fused endoperoxides
复制标题
Yb(OTf)(3)和可见光中继催化[3 2]环加成/[3,3]-重排/[4 2]环加成一锅制备恶嗪稠合内过氧化物
DOI：
10.1039/d0gc00929f
复制
发表时间：
2020
期刊：
影响因子：
9.8
通讯作者：
Mo Dong-Liang
中科院分区：
文献类型：
--
作者：
Ma Xiao-Pan;Nong Cai-Mei;Liang Yu-Feng;Xu Pei-Pei;Guo Xiu-Yun;Liang Cui;Pan Cheng-Xue;Su Gui-Fa;Mo Dong-Liang
本文报道了一种高立体选择性合成高取代恶嗪稠合内过氧化物的接力催化方法。该多米诺反应基于Yb（OTf）3和可见光促进的[3 + 2]环加成/[3，3]-重排，以及在温和的反应条件下，由N-乙烯基-α，β-不饱和硝酮和亚甲基环丙烷与空气在一锅中原位[4 + 2]环加成，导致密集取代的氧氮杂环丁烷的实际组装，含有五个立体中心的稠合内过氧化物，具有宽的底物范围和优异的非对映选择性。机理研究表明，内过氧化物环的O-O键来自于空气在白色LED下产生的单线态氧（1 O2）。此外，这种不对称中继催化剂也已实现以良好的对映选择性提供手性内过氧化物。生物学实验表明，所设计的恶嗪酮类内过氧化物能显著抑制LPS刺激的RAW264.7细胞产生一氧化氮（NO），具有良好的抗炎活性。
We report a relay catalysis for the highly stereoselective synthesis of densely substituted oxazonine-fused endoperoxides in good yields. This domino reaction is based on an Yb(OTf)3 and visible light promoted [3 + 2] cycloaddition/[3,3]-rearrangement, and in situ [4 + 2] cycloaddition with air in one pot under mild reaction conditions from N-vinyl-α,β-unsaturated nitrones and methylenecyclopropanes, leading to a practical assembly of densely substituted oxazonine-fused endoperoxides containing five stereocenters with a wide substrate scope and excellent diastereoselectivity. Mechanistic studies reveal that the O–O bond of the endoperoxide ring is derived from singlet oxygen (1O2) generated by air under a white LED. Moreover, such an asymmetric relay catalyst has also been realized to afford chiral endoperoxides in good enantioselectivity. Biological tests show that the designed oxazonine-fused endoperoxides significantly inhibited nitric oxide (NO) generation in LPS-stimulated RAW264.7 cells and exhibited their bioactivity as good anti-inflammatory agents.