Synthesis of 3,4,5-trisubstituted phenols via Rh(III)-catalyzed alkenyl C-H activation assisted by phosphonium cations.

An efficient method for the construction of various 3,4,5-trisubstituted phenol derivatives has been achieved via the Rh(III)-catalyzed coupling of phosphonium cations with internal alkynes. This protocol shows good substrate compatibility, as an array of structurally and electronically diverse phosphonium compounds react efficiently with up to 87% yield.