Oxaspiropentyl ketones and acetals prepared from α-cyclopropylidene ketones and acetals undergo, with lithium halides, isomerisation to 2-acylcyclobutanones and monoacetals.
Cycloaddition of Fluorenone <i>N</i>-Aryl Nitrones with Methylenecyclopropanes and Sequential 1,3-Rearrangement: An Entry to Synthesis of Spirofluorenylpiperidin-4-ones
作者:Xiao-Pan Ma、Jie-Feng Zhu、Si-Yi Wu、Chun-Hua Chen、Ning Zou、Cui Liang、Gui-Fa Su、Dong-Liang Mo
DOI:10.1021/acs.joc.6b02544
日期:2017.1.6
highly selective 1,3-rearrangement to give the desired product. The stereochemistry of the spirofluorenylpiperidin-4-one could be controlled by the cycloaddition and sequential rearrangement strategy. Furthermore, the spirofluorenylpiperidin-4-ones could be not only prepared in one-pot procedure but also converted to useful scaffolds by reduction or oxidation conditions.
[4 + 2] Cycloaddition of thiophene S-monoxides to activated methylenecyclopropanes
作者:Thies Thiemann、Daisuke Ohira、Yuanqiang Li、Tsuyoshi Sawada、Shuntaro Mataka、Karsten Rauch、Mathias Noltemeyer、Armin de Meijere
DOI:10.1039/b003850o
日期:——
determined as being endo,syn. The Wittig olefination of cyclopropanone hemiacetal to generate the methylenecyclopropanes and the subsequent cycloaddition can be carried out in a one-pot operation. This procedure is one of many potential one-pot or multi-component reactions involving stabilized phosphoranes. A further example of this type of reaction is shown in the novel desilylation–Wittig olefination
An Yb(OTf)<sub>3</sub> and visible light relay catalyzed [3 + 2] cycloaddition/[3,3]-rearrangement/[4 + 2] cycloaddition in one pot to prepare oxazonine-fused endoperoxides
作者:Xiao-Pan Ma、Cai-Mei Nong、Yu-Feng Liang、Pei-Pei Xu、Xiu-Yun Guo、Cui Liang、Cheng-Xue Pan、Gui-Fa Su、Dong-Liang Mo
DOI:10.1039/d0gc00929f
日期:——
We report a relay catalysis for the highly stereoselective synthesis of densely substituted oxazonine-fused endoperoxides in good yields. This dominoreaction 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
我们报告了中继催化高立体选择性合成高取代度的恶唑酮融合的内过氧化物的良率。此多米诺反应基于Yb(OTf)3和可见光促进的[3 + 2]环加成/ [3,3]重排,以及在空气中在温和的反应条件下在一个锅中用空气原位[4 + 2]环加成。N-乙烯基-α,β-不饱和的硝酮和亚甲基环丙烷,导致实际组装的稠密取代的恶嗪酮稠合的内过氧化物含有五个立体中心,具有宽的底物范围和出色的非对映选择性。机理研究表明,内过氧化物环的O–O键源自单重态氧(1 O 2)由白色LED下的空气产生。此外,还已经实现了这种不对称继电催化剂,以良好的对映选择性提供手性内过氧化物。生物学测试表明,设计的恶唑酮融合的内过氧化物显着抑制LPS刺激的RAW264.7细胞中一氧化氮(NO)的产生,并表现出它们作为良好的消炎药的生物活性。
Addition reactions to α-cyclopropylidene ketones and aldehydes.