Cu‐Promoted Sydnone Cycloadditions of Alkynes: Scope and Mechanism Studies
作者:Júlia Comas‐Barceló、Robert S. Foster、Béla Fiser、Enrique Gomez‐Bengoa、Joseph P. A. Harrity
DOI:10.1002/chem.201406118
日期:2015.2.16
reaction of sydnones and terminal alkynes, providing significant reduction in reaction times. Specifically, the use of Cu(OTf)2 is found to provide 1,3‐disubstituted pyrazoles, whereas simply switching the promoter system to Cu(OAc)2 allows the corresponding 1,4‐isomers to be produced. The mechanism of the Cu‐effect in each case has been investigated by experimental and theoretical studies, and they
Divergent Synthesis of Pyrazoles via Manganese Pincer Complex Catalyzed Acceptorless Dehydrogenative Coupling Reactions
作者:Koushik Sarkar、Pramod Kumar、Arjun Mule、Biplab Maji
DOI:10.1002/chem.202401105
日期:2024.6.25
defined Mn(I)-complex catalyzed acceptorless dehydrogenative coupling (ADC) reactions employing alcohols as the carbon source enabled the synthesis of multi-substituted pyrazoles. Symmetrical pyrazoles were made via the coupling of 1,3-diols with hydrazines. The unsymmetrically substituted pyrazoles were created using the ADC reaction of primary alcohols with hydrazones.
作者:Duncan L. Browne、John B. Taylor、Andrew Plant、Joseph P. A. Harrity
DOI:10.1021/jo902514v
日期:2010.2.5
The cycloaddition of 4-iodosydnones with terminal alkynes proceeds with excellent regiocontrol to provide 5-iodo pyrazoles. These products participate smoothly in subsequent C-C and C-heteroatom bond forming processes.