By treatment with an excess of lithium aluminum hydride, 1-(1'-hydroxy-2', 6', 6'-trimethylcyclohexyl) but-1-yn-3-ol (I) was converted to 1-(2', 6', 6'-trimethylcyclohexylidene) but-1-en-3-ol (II), which was further oxidized to the corresponding allenone (III), a new isomer of ionone, by the action of activated manganese dioxide.
