monosubstituted allenes in the presence of catalytic amounts of copper(I) chloride gives 1,3,5-substituted pyrazoles under mild conditions and very short reaction times. This site- and regioselective process involves first the complexation of copper(I) on the external double bond of the allene moiety, followed by nucleophilic attack on the central carbon atom of the so-formed copper(I)-complexed allene by the
When Hydrazonoyl Chlorides Meet Terminal Alkynes: Regioselective Copper(I)-Catalysed "Click" Sequential Reactions to 5-Substituted Pyrazoles
作者:Giorgio Molteni
DOI:10.3987/com-20-14268
日期:——
In the presence of catalytic amounts of copper(I) salts, terminal alkynes underwent the formation of copper(I) acetylides that enabled their nucleophilic addition onto hydrazonoyl chlorides followed by spontaneous cyclisation of the resulting alkynylhydrazone intermediate. This sequential reaction sequence was exploited as a facile and regioselective synthesis of 1,3,5-substituted pyrazoles. A catalytic
Regiocontrolled Synthesis of Ring-Fused Thieno[2,3-c]pyrazoles through 1,3-Dipolar Cycloaddition of Nitrile Imines with Sulfur-Based Acetylenes
作者:Jay Zumbar Chandanshive、Bianca Flavia Bonini、Denis Gentili、Mariafrancesca Fochi、Luca Bernardi、Mauro Comes Franchini
DOI:10.1002/ejoc.201001048
日期:2010.11
1,3-Dipolarcycloadditions of C-carboxymethyl-N-arylnitrile imines with substituted acetylenes bearing thiol or sulfone groups were studied. The sulfur controls the regiochemistry of the reaction, and this protocol was applied to the synthesis of ring-fused thieno[2,3-c]pyrazoles.
Synthesis and Characterization of Oxadisilole-Fused 1<i>H</i>-Benzo[<i>f</i>]indazoles and 1<i>H</i>-Naphtho[2,3-<i>f</i>]indazoles
作者:Yajuan Zhang、Xuyan Ma、Yali Chen、Xuanming Chen、Lei Guo、Weiguo Cao、Jie Chen、Man Shing Wong
DOI:10.1002/ejoc.201300110
日期:2013.5
1H-benzo[f]- and 1H-naphtho[2,3-f]indazoles have been synthesized by the 1,3-dipolar cycloaddition reactions of benzo- or naphtho-oxabicycloalkenes with nitrile imines generated in situ from N-arylhydrazonoyl chlorides followed by deoxygenation and aromatization. The photophysical, redox and thermal properties of these compounds have been characterized. Some of the indazoles show potential as deep-blue emitters
1,3-Dipolar Cycloaddition of Nitrile Imines with Cyclic α-β-Unsaturated Ketones: A Regiochemical Route to Ring-Fused Pyrazoles
作者:Jay Zumbar Chandanshive、Bianca Flavia Bonini、William Tiznado、Carlos A. Escobar、Julio Caballero、Cristina Femoni、Mariafrancesca Fochi、Mauro Comes Franchini
DOI:10.1002/ejoc.201100558
日期:2011.7.8
1,3-Dipolarcycloadditions of C-carboxymethyl-N-arylnitrile imines with cyclic α,β-unsaturated ketones of various sizes have been studied. After cycloaddition, oxidative aromatization gives the ring-fusedpyrazoles. Computational studies and the use of topological analyses of the Fukui functions allows a theoretical description of the local reactivity that is in agreement with the experimentally observed