(2S)-1-[(1R)-1-[bis(1,1-dimethylethyl)phosphino]ethyl]-2-(dicyclohexylphosphino)ferrocene, commonly known as Josiphos SL-J009-1, is a chiral ferrocenyl diphosphine ligand. It features a ferrocene backbone asymmetrically substituted with a dicyclohexylphosphino group and a tert-butylphosphinoethyl group, creating a well-defined chiral environment. This compound is a member of the prominent Josiphos ligand family, which are known for their modular structure and tunable steric and electronic properties. This ligand is primarily employed in asymmetric catalysis, particularly in transition metal-catalyzed reactions. Its key application is in enantioselective hydrogenation reactions, where it forms highly active and selective catalysts with metals like rhodium and ruthenium. It is extensively used in the industrial-scale synthesis of chiral pharmaceutical intermediates and fine chemicals, enabling the production of single enantiomers with high efficiency and selectivity. The specific stereochemistry (S,R) of this variant is crucial for achieving the desired enantioselectivity in target transformations. As a sophisticated, pre-formed chiral ligand, it is not a generic synthetic building block but a specialized tool for advanced synthetic chemistry. Its use is confined to catalytic applications in research and process development within the pharmaceutical and specialty chemical industries. Proper handling requires consideration of its air- and moisture-sensitive phosphine groups.