Phenacyl Xanthates: A Photoremovable Protecting Group for Alcohols under Visible Light

Abstract The utility of phenacyl xanthates for the protection of hydroxyl groups is reported herein. Phenacyl xanthates are readily prepared via a one‐pot procedure, which employs the commercially available, inexpensive 2‐bromoacetophenone and carbon disulphide. The introduction of phenylcarboxymethyl dithiocarbonates could be achieved in good to excellent yield in the presence of ester group or ketal group. The hydroxyl group can be released in the presence of ethidine under irradiation of visible light without photocatalyst. The phenacyl xanthates could be selectively removed without affecting a series of common protecting groups, such as benzoate, tetrahydropyran and ketal groups. Finally, a plausible mechanism of photocleavage of phenacyl xanthates has been discussed.