Enantiodivergent Sulfoxidation Catalyzed by a Photoswitchable Iron Salen Phosphate Complex

Abstract

AbstractHere we describe a photoswitchable iron(III) salen phosphate catalyst, which is able to catalyze the enantiodivergent oxidation of prochiral aryl alkyl sulfides to chiral aryl alkyl sulfoxides. The stable (S)‐axial isomer of the catalyst produced enantioenriched sulfoxides with the (R)‐configuration in up to 75 % e.e., whereas the photoisomerized metastable (R)‐axial isomer of the catalyst favored the formation of (S)‐sulfoxides in up to 43 % e.e. The maximum Δe.e. value obtained in the enantiodivergent sulfoxidation was 118 %, which is identical to the maximum Δe.e. value that was measured in the enantiodivergent epoxidation of alkenes by a related recently described Mn1 catalyst. This iron‐based catalyst broadens the scope of photoswitchable enantiodivergent catalysts and may be used in the future to develop a photoswitchable catalytic system that can write digital information on a polymer chain in the form chiral sulfoxide functions.