Enantioselective Synthesis of Functionalized Pyrazoles by NHC-Catalyzed Reaction of Pyrazolones with α,β-Unsaturated Aldehydes
作者:Santhivardhana Reddy Yetra、Santigopal Mondal、Eringathodi Suresh、Akkattu T. Biju
DOI:10.1021/acs.orglett.5b00293
日期:2015.3.20
The N-heterocyclic carbene (NHC)-organocatalyzed enantioselectiveannulation reaction of pyrazolones with α,β-unsaturated aldehydes proceeding via the chiral α,β-unsaturatedacylazolium intermediates under oxidative conditions is presented. The reaction afforded dihydropyranone-fused pyrazoles in moderate to good yields and good er values under operationally simple and base-free conditions.
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
SO<sub>2</sub>F<sub>2</sub> mediated transformation of pyrazolones into pyrazolyl fluorosulfates
作者:Jing Leng、Hua-Li Qin
DOI:10.1039/c9ob00903e
日期:——
The construction of a class of novel N-heterocyclic molecules containing both pyrazole and fluorosulfate functionalities was achieved through the reactions of pyrazolones with SO2F2 in good to excellent yields. The fluorosulfate moieties were utilized as versatile building blocks in the Suzuki coupling reaction and SuFEx click chemistry.
通过吡唑啉酮与SO 2 F 2的反应,以良好至极好的收率,可以实现一类同时具有吡唑和氟硫酸盐官能团的新型N-杂环分子的构建。在Suzuki偶联反应和SuFEx click化学中,氟代硫酸盐部分被用作通用的结构单元。
Multicomponent reactions of 1,3-disubstituted 5-pyrazolones and formaldehyde in environmentally benign solvent systems and their variations with more fundamental substrates
作者:Jia-Neng Tan、Minghao Li、Yanlong Gu
DOI:10.1039/b924699a
日期:——
Many multicomponentreactions (MCRs) of 1,3-disubstituted 5-pyrazolones and formaldehyde were developed in environmentally benign solvent systems. Styrenes, vinylferrocene and 2-phenylindoles could easily react, under solvent-free conditions or in glycerol solvent, with 1,3-disubstituted 5-pyrazolones and paraformaldehyde in the absence of any catalyst to afford a variety of complex skeletons in moderate
Catalytic Enantioselective Addition of Pyrazol-5-ones to Trisubstituted Nitroalkenes with an <i>N</i>
-Sulfinylurea Organocatalyst
作者:James P. Phelan、Jonathan A. Ellman
DOI:10.1002/adsc.201600110
日期:2016.6.2
The first example of enantioselective nitronate protonation following Michaeladdition of a carbon nucleophile to an α,β,β‐trisubstituted nitroalkene is reported. An N‐sulfinylurea catalyst was employed to catalyze the addition of a variety of 3‐substituted pyrazol‐5‐one nucleophiles to trisubstituted nitroalkenes incorporating an oxetane or azetidine ring at the β‐position. The nitroalkane‐pyrazolone