1,1,1,4,4,4-Hexafluorobut-2-yne (HFB) as a Versatile Dipolarophile for [3+2] Cycloaddition with 1,3-Dipoles toward Azoles with Adjacent CF3 Groups

This project involves the syntheses of novel pyrazoles, pyrazolines and isoxazoles with two CF3 groups via 1,3-dipolar cycloaddition reaction of 1,1,1,4,4,4-hexafluorobut-2-yne (HFB) with diazocompounds, azomethine imines and nitrile oxides, respectively. Conditions for these azoles preparation differ in catalyst-free mild manners and are applicable to a wide range of substrates, while demonstraiting a high functional group tolerance with yields of target heterocycles from moderate to excellent. Indeed, pyrazolines bearing two adjacent CF3 groups are practically unknown up to date.