30020-83-8Relevant academic research and scientific papers
Enantioselective Syntheses of C2-Symmetric Pyrazolones and Diones via One-Pot Organo-/Iodine Sequential Catalysis
Feng, Kai-Xiang,Tang, Cheng-Ke,Shen, Qiao-Yu,Xia, Ai-Bao,Huang, Li-Sha,Zhou, Zhan-Yu,Zhang, Xing,Du, Xiao-Hua,Xu, Dan-Qian
, p. 6750 - 6755 (2021)
The catalytic diastereo- and enantioselective syntheses of C2-symmetric axially chiral 1,4-dicarbonyl derivatives with 2,3-quaternary stereocenters were achieved by utilizing an organo-/iodine binary catalytic strategy. The reactions proceeded well under
Bifunctional squaramide-catalyzed one-pot sequential Michael addition/dearomative bromination: Convenient access to optically active brominated pyrazol-5(4H)-ones with adjacent quaternary and tertiary stereocenters
Wang, Huanxia,Wang, Youming,Song, Haibin,Zhou, Zhenghong,Tang, Chuchi
, p. 4844 - 4851 (2013/08/23)
The organocatalytic asymmetric, one-pot, sequential Michael addition/dearomative bromination reaction of pyrazol-5-ones to nitro olefins and N-bromosuccinimide (NBS) has been developed. Under the catalysis of a chiral bifunctional squaramide, a wide variety of chiral brominated pyrazol-5-one derivatives with contiguous quaternary and tertiary stereocenters was obtained in high yields (up to >99 %) with good to excellent diastereoselectivities (62:38-99:1 dr) and uniformly high levels of enantioselectivity (92 to >99 % ee). This experimentally simple process facilitates access to various enantioenriched, multiply substituted pyrazolin-5-one derivatives, potential biologically active molecules, starting from readily available starting materials. Copyright
