Two-Step Synthesis of 2-Trifluoromethylated and 2-Difluoromethylated Benzoheteroles Starting from HFO-1224yd() and HFO-1233yd().

An efficient two-step method for synthesizing 2-(trifluoromethyl)- and 2-(difluoromethyl)benzoheteroles bearing various substituents was developed. Commercially available HFO-1224yd() or HFO-1233yd() underwent the Suzuki-Miyaura coupling with arylboronic acids (acid esters) bearing a nucleophilic moiety at the position to yield the corresponding β-fluoro-β-(trifluoromethyl)- or β-fluoro-β-(difluoromethyl)styrenes, respectively. Treatment of the obtained styrenes with potassium phosphate induced nucleophilic 5-- cyclization to provide the corresponding 2-trifluoromethylated or 2-difluoromethylated indoles and benzofurans, as well as benzothiophenes.