An efficient synthesis of 1,3,5-trisubstituted pyrazoles from N-alkylated tosylhydrazones and terminal alkynes was developed. The protocol was applied to a wide range of substrates and demonstrated excellent tolerance to a variety of substituents, including both electron-donating and -withdrawing groups. In comparison with the common approaches for substituted pyrazole syntheses, this methodology proceeded with complete regioselectivity, especially, in the cases that R2 and R3 are similar substituents.

An efficient synthesis of pyrazoles from tosylhydrazones and nitroalkenes was developed. In comparison with the previously reported 1,3-dipolar cycloaddition reaction of diazo compounds with electron-deficient alkenes or alkynes, this methodology proceeded with a sequential Baylis–Hillman/intramolecular cyclization mechanism and a variety of reversed regioselectivity products were prepared in good yields.

An efficient synthesis of pyrazoles from tosylhydrazones and nitroalkenes was developed. In comparison with the previously reported 1,3-dipolar cycloaddition reaction of diazo compounds with electron-deficient alkenes or alkynes, this methodology proceeded with a sequential Baylis–Hillman/intramolecular cyclization mechanism and a variety of reversed regioselectivity products were prepared in good yields.