Kinetic resolution of phenyl methyl sulfoxides by mammalian methionine sulfoxide reductase A

•Chiral sulfoxides are of great interest as chiral auxiliaries in organic synthesis.•An enzymatic kinetic resolution of aryl methyl sulfoxides is proposed.•Methionine sulfoxide reductase A (MsrA) reduces in vivo Sc-Met-Ss-sulfoxide to Sc-Met.•We show here that MsrA reduces the S enantiomer of some aryl methyl sulfoxides.•MsrA is suggested for the large-scale preparation of optically pure sulfoxides.