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。
Asymmetric synthesis of atropisomeric pyrazole <i>via</i> an enantioselective reaction of azonaphthalene with pyrazolone
作者:Huijun Yuan、Yao Li、Hanhui Zhao、Zhihong Yang、Xin Li、Wenjun Li
DOI:10.1039/c9cc06360a
日期:——
The first catalytic asymmetricreaction of azonaphthalene with pyrazolone has been established. A wide range of axially chiral pyrazole derivatives have been achieved in good yields (68–99%) with excellent enantioselectivities (83–98% ee) by utilizing chiral phosphoric acid as a catalyst. This strategy provides an efficient and facile approach for the construction of axially chiral pyrazole derivatives