Catalytic Cleavage of Benzyl Ethers
Catalytic Benzyl Ether Cleavage: Application in Natural Product Synthesis
Synthetically, benzyl ethers are used as protecting groups for hydroxyl groups. The benzyl ethers can be easily hydrogenated to the corresponding alcohols under neutral conditions.
The synthesis of a sesquiterpene is chosen here as an example for such an application. In the first step of the synthesis, the hydroxyl group is transformed into a benzyl ether using the Williams ether synthesis. The benzyl ether is unreactive under the conditions of the subsequent steps (carbonyl group deprotection, Wittig reaction, hydroboration, oxidation, and methylation). In the last step, the hydroxyl group is regenerated by catalytic cleavage of the benzyl ether.