Stereoselective\nSynthesis of Chiral <i>C</i><sub>2</sub>‑Symmetric\n1,3- and 1,5-Bis-Sulfoxides Guided\nby the Horeau Principle: Understanding the Influence of the Carbon\nChain Nature in Its Ability for Metal Coordination

The stereoselective synthesis of two distinct types of <i>C</i><sub>2</sub>-symmetric chiral bis-sulfoxides, 1,3- and\n1,5-bis(sulfinyl) derivatives, has been achieved based on the DAG\nmethodology. The 1,5-bis(sulfinyl) derivatives constitute a new family\nof tridentate chiral ligands thanks to the presence of an additional\nsulfenyl or sulfinyl group in the carbon chain acting as a bridge.\nA systematic development and optimization of two synthetic routes,\none for each ligand family, have been undertaken, highlighting the\nstrategic utilization of Horeau’s law to enhance enantioselectivity.\nAdditionally, palladium (Pd) and ruthenium (Ru) complexes derived\nfrom the synthesized bis-sulfoxides were prepared, and their structures\nwere elucidated through spectroscopic analysis. Isolation of Pd(II)\ncomplexes involving 1,3-bis-sulfoxides was exclusively achieved using\ntrifluoroacetates as coligands. In the case of Ru(II) complexes, the\ntrans geometry could be determined for 1,3-bis-sulfoxides. The introduction\nof a third sulfur atom as a coordinating element in the 1,5-bis(sulfinyl)\nderivatives facilitates the formation of two distinct tricoordinated\nRu(II) complexes. The structure of these complexes is intricately\ninfluenced by the oxidation state adopted by the central sulfur on\nthe chain, whether as a thioether or as a sulfoxide.