A General and Regioselective Synthesis of 5-Trifluoromethyl-pyrazoles
作者:Robert S. Foster、Harald Jakobi、Joseph P. A. Harrity
DOI:10.1021/ol3021918
日期:2012.9.21
Two synthetic approaches to 4-trifluoromethylsydnones, a novel class of these mesoionic reagents, are reported. These compounds undergo regioselective alkyne cycloaddition reactions, thereby providing a generalapproach to 5-trifluoromethylpyrazoles. This method has been employed in a short formal synthesis of the herbicide fluazolate.
Synthesis of 4-Fluoromethylsydnones and their Participation in Alkyne Cycloaddition Reactions
作者:Robert S. Foster、Harry Adams、Harald Jakobi、Joseph P. A. Harrity
DOI:10.1021/jo400381a
日期:2013.4.19
We report the synthesis and some structural studies of 4-trifluoromethyl, 4-difluoromethyl-, and 4-monofluoromethylsydnones. All but the latter compounds are stable and represent effective precursors to a range of pyrazoles after cycloadditionreactions with alkynes. The cycloadditions are generally highly regioselective and provide 5-fluoromethylpyrazole products, although we have observed that Bn-substituted