Theoretical calculations of chemical interactions. Part 6. An MNDO study of the intermediates involved in CO insertion into lithium–nitrogen bonds in lithium dialkylamides

Abstract

Carbon monoxide insertion into Li–N bonds in lithium dialkylamides provides a useful synthetic method not only for substituted formamides but also for highly functionalized compounds such as substituted glyoxylamides and tartronamides. The high instability of the intermediates involved precludes direct independent determination of the various steps involved but theoretical calculations provide a way of predicting their feasibility. Both INDO and MNDO procedures have been used but the MNDO method has been found to be more appropriate for this study. The geometries and energies of the proposed intermediates have been calculated as well as the equilibrium positions for several acid–base equilibria and the energy changes involved in the different steps. An estimation of the solvent interaction with the charged intermediates has allowed a prediction of the temperature effect which is consistent with the observed experimental results.