Synthesis of Fully Substituted Pyrazoles via Regio- and Chemoselective Metalations

The full functionalization of the pyrazole ring was achieved by successive regioselective metalations using TMPMgCl center dot LiCl and TMP2Mg center dot 2LiCl. Trapping with various electrophiles led to trisubstituted pyrazoles. An application to the synthesis of the acaricide Tebufenpyrad is reported.