Chemoselective Synthesis of Substituted Pyrazoles Through AgOTf-Catalyzed Cascade Propargylic Substitution—Cyclization—Aromatization.

Silver-catalyzed reaction of propargylic alcohols (I) with tosylhydrazine leads to 3,5-disubstituted 1H-pyrazoles (II), whilst the analogous reaction of terminal alkynes (VII) gives rise to N-tosyl pyrazoles (VIII).