Asymmetric [3 + 3] Annulation of Copper–Allenylidenes with Pyrazolones: Synthesis of Chiral 1,4-Dihydropyrano[2,3-<i>c</i>]pyrazoles
作者:Feng Jiang、Xinping Feng、Rou Wang、Xing Gao、Hao Jia、Yumei Xiao、Cheng Zhang、Hongchao Guo
DOI:10.1021/acs.orglett.8b02214
日期:2018.9.7
The copper-catalyzed asymmetric [3 + 3] annulation of ethynyl benzoxazinanones with pyrazolones has been achieved, providing simple access to 1,4-dihydropyrano[2,3-c]pyrazole derivatives in moderate to excellent yields with excellent enantioselectivities (up to 99% ee). Compared with previous annulation reactions of copper–allenylidenes from ethynyl benzoxazinanones, the current reaction fused the
乙炔基苯并恶嗪酮与吡唑啉酮的铜催化不对称环化[3 + 3]已实现,可轻松获得1,4-二氢吡喃并[2,3- c ]吡唑衍生物,且产率中等至优异,对映选择性极佳(高达99 %ee)。与以前的乙炔基苯并恶嗪酮的铜-亚烯基环化反应相比,当前反应将炔丙基部分的三个碳原子融合成杂环骨架。