Hydroxide-promoted selective C(α)–C(β) bond activation of aliphatic ethers by rhodium(III) porphyrins

• Selective C(α)–C(β) bond activation of aliphatic ethers.
• Rhodium porphyrin hydroxides as intermediates.
• Ether oxidation by water to esters.

The selective aliphatic C(α)–C(β) bond activation (CCA) of ethers by rhodium(III) porphyrin halides in the presence of KOH was achieved to give Rh–C(β) alkyls up to 88% yield. The addition of H2O and a phase transfer agent Ph4PBr improved the homogeneity of the reaction mixture and significantly brought down the reaction temperature to 60 °C. At this mild temperature, the C(α) co-product was oxidized to the corresponding esters in up to 89% yield. KOH promotes the bond activation by transferring the hydroxyl group to rhodium porphyrin to generate the key intermediate RhIII(ttp)OH (ttp = 5,10,15,20-tetratolylporphyrinate dianion).

Selective C(α)–C(β) bond activation of aliphatic ethers.Figure optionsDownload as PowerPoint slide