Metalation of Ketazines. Interaction of Tetralone Azine with Methyllithium

The reaction of tetralone azine with methyllithium in tetrahydrofuran results in the release of 1 mol of СН and the formation of the lithium salt of enamine I, which crystallizes as a dimer in which the lithium atoms are bridges between the sp- and sp-nitrogen atoms of the two ligands and form a six-membered LiNNLiNN metallacycle (CCDC No. 2426300). Analysis of the electron density topology using the non-covalent interaction index and the source function allowed us to determine that each lithium atom in complex I interacts with the NNCC fragment of the ligand. The study of the charge distribution in the ligand anion demonstrated that the C(2) position is the most favorable for directing the attack of various electrophilic substrates. The DFT method showed that the process of phosphorylation of the deprotonated azine tetralone PCl is thermodynamically more favorable by 12.6 kcal/mol than the product of phosphorylation at the nitrogen atom.