Palladium-Catalyzed Reductive Insertion of Alcohols into Aryl Ether Bonds

Palladium on carbon catalyzes C-O bond cleavage of aryl ethers (diphenyl ether and cyclohexyl phenyl ether) by alcohols (R-OH) in H-2. The aromatic C-O bond is cleaved by reductive solvolysis, which is initiated by Pd-catalyzed partial hydrogenation of one phenyl ring to form an enol ether. The enol ether reacts rapidly with alcohols to form a ketal, which generates 1-cyclohexenyl-O-R by eliminating phenol or an alkanol. Subsequent hydrogenation leads to cyclohexyl-O-R.