Hemicryptophane, a covalent molecular capsule that is composed of a cyclotriveratrylene (CTV) host unit, a tris(2-aminoethyl)amine (tren) ligand, and three rigid phenyl spacers, is a useful ligand for preparing synthetic transition metal complexes containing well-defined cavities that mimic the active sites of metalloenzymes. A method for the selective oxidation of primary alcohols using 5 mol % hemicryptophane-ruthenium(II) dichloride as the catalyst and cerium(IV) ammonium nitrate (CAN) as the terminal oxidant is described. The corresponding aldehydes of both benzylic and aliphatic alcohols are afforded in good to excellent yields under mild conditions without significant over-oxidation to produce the corresponding carboxylic acids.
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