Redox-Active Ligand-Assisted Ruthenium-Catalyzed Lemieux–Johnson-Type Oxidation of Olefins for Aldehyde Synthesis

Abstract

This work presents a ruthenium complex catalyst bearing redox-active ligands for highly selective oxidative cleavage of alkenes. The ligand serves as a dynamic electron reservoir with two core functions. Reversible electron transfer between the ligand and the Ru center generates high-valent Ru(V)═O/Ru(VI) active species to drive C═C bond scission. Meanwhile, stable coordination modulates the metal’s electron density and steric environment, suppressing ligand decomposition and overoxidation of aldehyde intermediates into carboxylic acids. Conducted at room temperature in an ethyl acetate–water mixed solvent, the optimized system delivers outstanding chemoselectivity: C═C substrates are selectively cleaved into aldehydes, whereas C≡C substrates are converted to α-diketones. The catalyst features wide substrate compatibility, efficiently transforming monoterpenes, amino acid derivatives, and nonsteroidal anti-inflammatory drugs. This study establishes an efficient route for selective functional group modification of structurally intricate molecules.