Enantioselective Palladium-Catalyzed Hydrofluorination of Alkenylarenes
Xuemei Yin, Bin Chen, Feng Qiu, Xihong Wang, Yang Liao, Min Wang, Xinxiang Lei, Jian Liao
Abstract
Hydrofluorination of simple alkenes is an attractive strategy to prepare fluorine-containing molecules. However, the catalytic asymmetric hydrofluorination remains an ongoing challenge. Here, we describe a palladium(II)-catalyzed enantioselective hydrofluorination of alkenylarenes, by employing sulfoxide phosphine (SOP) as a chiral ligand, triarylphosphine as a secondary ligand, Selectfluor as a fluorine source, and trihexylsilane as a hydride source. Under the optimal reaction conditions, a range of chiral benzyl fluorides bearing different functional groups are obtained in good yields (up to 80%) with high enantiopurity (having an enantiomeric ratio of up to 94:6). Some mechanistic insight of this reaction is obtained using in situ one- and two-dimensional 1H–31P HMBC nuclear magnetic resonance spectroscopy and a catalytic cycle is proposed.