Iodine-mediated synthesis of 4-selanylpyrazoles

Abstract

A new and simple procedure mediated by I₂ is developed for the preparation of 4-selanylpyrazoles from pyrazoles and diselenides. This metal-free protocol is convenient under neutral conditions at room temperature in a short time, and is suitable for a wide variety of starting materials and provides a series of 4-selanylpyrazoles in moderate to good yields. A plausible electrophilic substitution mechanism is hypothesized.