The efficient synthesis of chiral compounds is a key requirement for the synthesis of active pharmaceutical ingredients (APIs). Enzymes have a unique advantage over conventional chemistries, due to their innate high stereo-, regio-, and chemo-selectivities, and have emerged as a powerful tool in synthetic routes, as highlighted by recent examples from industry such as Merck's routes to islatravir 2 and nemtabrutinib, Pfizer's route to abrocitinib, or GSK's route to GSK2879552. Many enzymatic classes have been employed in the synthesis of chiral alcohols and amines (Figure ), two key functional groups in many APIs; however, the same is not true for other important functional groups, such as thiols and thioethers (Figure ). Indeed, only few examples exist for the biocatalytic synthesis of thiols and thioethers (Figure ), most of which start from racemic compounds and employ (dynamic) kinetic resolutions. Their synthesis by chemical means, such as metal catalysis, is also challenging due to the poisoning effect of sulfur on many metal catalysts. Furthermore, the reactivity of thiols further complicates enantiocontrol due to uncatalyzed background reactivity.