Formation and stability of alkoxyimidates in the cyclobutane bicyclobutane system

The reactions of CN^- with methyl-3-chlorobicyclobutanecarboxylate and 3-chloro and 3-bromobicyclobutanecarbonitrile in MeOH were investigated. The MeO^- present in the reaction mixture adds reversibly to the carbonitrile function of the various products. The equilibrium constants for the imidate formation were determined. The general notion that the imidate form is favored by an electron withdrawing group was reconfirmed. The order found was CN>Cl ≈ Br>C(NH)OMe>CO₂Me. It was also found that the central bond of bicyclobutane is a good mediator for transmittance of electronic effects. The unique stability of the alkoxyimidates compared to the low stability of the corresponding adducts with CN^- is discussed.