A range of pyrazol-5-one and pyrazol-3-one derivatives has been synthesized in a single step via a palladium-catalyzed carbonylation of aromatic or aliphatic α-chloroketones, in the presence of aromatic or aliphatic hydrazines. A reaction mechanism, explaining the observed regioselectivity, has been also discussed.
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
Enantioselective synthesis of functionalized 1,4-dihydropyrazolo-[4′,3′:5,6]pyrano[2,3-<i>b</i>]quinolines through ferrocenyl-phosphine-catalyzed annulation of modified MBH carbonates and pyrazolones
An enantioselective synthesis of highly functionalized 1,4-dihydropyrazolo[4′,3′:5,6]pyrano[2,3-b]quinolines from modified MBH carbonates and pyrazolones via a chiral phosphine-mediated alkylation/annulation sequence has been realized. The chiral dihydropyrano[2,3-c]pyrazoles bearing bio-active condensed heterocycles were facilely formed in good chemical yields and with high to excellent enantioselectivity
通过手性膦介导的烷基化/环化反应,由改性的碳酸氢甲酯和吡唑酮类化合物实现了高官能化的1,4-二氢吡唑并[4',3':5,6]吡喃并[2,3- b ]喹啉的对映选择性合成。。带有生物活性的稠合杂环的手性二氢吡喃并[2,3- c ]吡唑通过使用少量催化剂而容易地以良好的化学收率和高至优异的对映选择性形成。