A mild and efficient protocol for the synthesis of fluorinated pyrazoles has been developed via gold(I)-catalyzed tandem aminofluorination of alkynes in the presence of Selectfluor. This method offers a broad substrate scope.
Fluorination of 3,5-diarylpyrazole substrates by Selectfluor (TM) in acetonitrile gave 4,4-difluoro-1H-pyrazoles in addition to 4-fluoropyrazole derivatives. The structure of this new class of fluorinated heterocycle was established by X-ray crystallography.
Continuous gas/liquid–liquid/liquid flow synthesis of 4-fluoropyrazole derivatives by selective direct fluorination
作者:Jessica R Breen、Graham Sandford、Dmitrii S Yufit、Judith A K Howard、Jonathan Fray、Bhairavi Patel
DOI:10.3762/bjoc.7.120
日期:——
4-Fluoropyrazole systems may be prepared by a single, sequential telescoped two-step continuousgas/liquid-liquid/liquid flow process from diketone, fluorinegas and hydrazine starting materials.