An environmentally benign and efficient synthesis of 4‐Selanylpyrazoles catalyzed by haloid salts in water

Abstract

An environmentally benign procedure is developed for the preparation of 4-selanylpyrazoles from pyrazoles and diselenides. Using haloid salts as catalysts and H 2 O 2 as oxidant, this catalytic protocol is convenient in water at room temperature under open-air condition, and is suitable for a wide variety of starting materials and provides a series of 4-selanylpyrazoles in good yields. A plausible catalytic electrophilic substitution mechanism is hypothesized.

Synthetic strategies for aryl/heterocyclic selenides and tellurides under transition-metal-catalyst free conditions

“…Yan et al reported haloid salt (bromide and iodide) promoted protocol for the preparation of 4-selanylpyrazoles from N -protected pyrazoles in presence of hydrogen peroxide as oxidant in water at room temperature ( Scheme 22 ). 38 …”