Palladium-Catalyzed Enantioselective Arylation of Aryl Sulfenate Anions: A Combined Experimental and Computational Study

A novel approach to produce chiral
diaryl sulfoxides from aryl
benzyl sulfoxides and aryl bromides via an enantioselective arylation
of aryl sulfenate anions is reported. A (JosiPhos)­Pd-based catalyst
successfully promotes the asymmetric arylation reaction with good
functional group compatibility. A wide range of enantioenriched diaryl,
aryl heteroaryl, and even diheteroaryl sulfoxides were generated.
Many of the sulfoxides prepared herein would be difficult to prepare
via classic enantioselective oxidation of sulfides, including Ph­(Ph-d5)­SO (90% ee, 95% yield). A DFT-based computational
study suggested that chiral induction originates from two primary
factors: (i) both a kinetic and a thermodynamic preference for oxidative
addition that places the bromide trans to the JosiPhos-diarylphosphine
moiety and (ii) Curtin–Hammett-type control over the interconversion
between O- and S-bound isomers of
palladium sulfenate species following rapid interconversion between re- and si-bound transmetalation products, re/si-Pd–OSPh (re/si-PdO-trans).