Coordinating ability and versatility of organosulfur-based ligands in transition metal catalyzed hydrogenative and hydrogen auto-transfer processes

Transition metal complexes with sulfur-donor ligands serve as efficient catalysts in numerous homogeneous reactions, owing to the coordination diversity of sulfur-based ligands and the possibility to obtain chiral and achiral complexes. Historically dominated by phosphorus and nitrogen, transition metal compounds with electron-rich sulfur-donor ligands have recently attracted research interest because of their close connection with enzymatic transformation. This review presents a comprehensive overview of recent applications of sulfur-ligated metal complexes in hydrogenative and strictly related hydrogen auto-transfer processes, namely hydrogenation, transfer hydrogenation and borrowing hydrogen reactions. Particular attention is given to the impact of ligand selection on the reaction outcomes, and on the influence of sulfur to give stability at the catalytically active metal complex. Additionally, the review compares conventional hydrogenation and transfer hydrogenation strategies with emerging approaches involving metal-ligand cooperation in the presence of sulfur-based ligands.