N-Heterocyclic carbene-catalyzed SuFEx reactions of fluoroalkylated secondary benzylic alcohols

Abstract

An organocatalytic sulfur(VI)-fluoride exchange (SuFEx) reaction of secondary benzylic alcohols is reported. Under the catalysis of 10 mol% NHC, trifluoromethyl, difluoromethyl, bromodifluoromethyl, iododifluoromethyl, and pentafluoroethyl substituted secondary benzylic alcohols reacted with aryl sulfonyl fluorides or fluorosulfates to produce the corresponding sulfonates and sulfates in 62–99% yields. In these reactions, 4 Å molecular sieves were used as highly efficient HF scavengers, avoiding the use of stoichiometric amounts of silicon reagents and excess amounts of bases.