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Updated: Feb 12, 2026

Positron Emission Tomography Using 64-Copper as a Tracer for the Study of Copper-Related Disorders
Published on: April 28, 2023
Copper-mediated regioselective hydrodifluoroalkylation of alkynes
Xiaorui Feng1, Xiaoyang Wang, Hongtai Chen
1Tianjin Key Laboratory of Molecular Optoelectronic Science, Department of Chemistry, School of Science, Tianjin University, Tianjin 300072, P. R. China. wanggw@tju.edu.cn.
Abstract:
A highly regioselective copper-mediated hydrodifluoroalkylation of alkynes with ethyl bromodifluoroacetate or bromodifluoroacetamides has been developed. This strategy provides straightforward access to a variety of difluoroalkylated alkenes under mild reaction conditions with low-cost cuprous bromide and metabisulfite as reduction agents. A wide range of alkynes are applicable under these reaction conditions. The excellent functional-group compatibility and good regio- and stereoselectivities are the notable features of this transformation.
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The acidic strength of hydrocarbons follows the order: Alkynes > Alkenes > Alkanes. The strength of an acid is commonly expressed in units of pKa — the lower the pKa, the stronger the acid. Among the hydrocarbons, terminal alkynes have lower pKa values and are, therefore, more acidic. For example, the pKa values for ethane, ethene, and acetylene are 51, 44, and 25, respectively, as shown here.
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