Hydrophobic vitamin B₁₂. 8. Carbon-skeleton rearrangement reactions catalyzed by hydrophobic vitamin B₁₂ in octopus azaparacyclophane

Heptapropyl cobyrinate perchlorate catalyzed the carbon-skeleton rearrangements, which convert 2-acetyl-2-ethoxycarbonylpropane, 2-cyano-2-ethoxycarbonylpropane, 1-acetyl-1-ethoxycarbonylethane, and diethyl β-methyl-dl-aspartate into 1-acetyl-2-ethoxycarbonylpropane, 2-cyano-1-ethoxycarbonylpropane and 1-cyano-2-ethoxycarbonylpropane, 1-acetyl-2-ethoxycarbonylethane, and diethyl glutamate, respectively, in an octopus cyclophane placed in aqueous carbonate buffer (pH 7.0) at 20.0°C by utilizing vanadium trichloride as a cocatalyst under aerobic photolysis conditions. The migratory aptitude of the electron-withdrawing groups was found to follow the sequence: CN ≈ CO₂C₂H₅ < COCH₃. Yields of the rearrangement products were very low in the absence of heptapropyl cobyrinate perchlorate.