Organophotoredox Catalyzed C‒O Bond Cleavage: A Chemoselective Deprotection Strategy for Phenolic Ethers and Esters Driven by the Oxophilicity of Silicon

An organo-photocatalyzed approach for the chemoselective dealkylation and de-esterification of phenols is developed by employing trimethyl silyl chloride as the C‒O bond activator and 9-Mes-10-MeAcr+ClO4‒ as the photoredox catalyst. This method demonstrates an exceptional selectivity towards the cleavage of phenolic ethers and esters over equivalent aliphatic scaffolds, presenting a broad range of functional group sustainability. This strategy also enables selective debenzylation of phenols in the presence of reduction-sensitive functional groups. The photocatalytic efficiency was further extrapolated in the fragmentation of lignin models and synthetic modification in manufacturing a FLAP inhibitor. Mechanistic studies, photophysical experiments and computations provide evidence for the involvement of an oxonium intermediate, generated through the photo-oxidation of the arene ring, which ultimately leads to the selective disintegration of C‒O bond, facilitated by the oxophilicity of silicon.