Metal-Induced C–N Bond Cleavage in the Decomposition of Alkali (R,R)‑Bis(α-methylbenzyl)amide Complexes

This study resulted in the isolation of new alkali metal complexes of (R,R)-bis­(α-methylbenzyl)­amine (B-α-mba) characterized by NMR spectroscopy and single-crystal X-ray diffraction where possible. The reaction outcome was found to be dependent on metal and Lewis donor choice to afford species [{PhCH­(CH3)}2NLi·Dioxane]2 2, [{PhCH­(CH3)}2­NLi·HMPA]2 3, [{PhCH­(CH3)}2­NLi·TMEDA] 4, and [{PhCH­(CH3)}2­NNa·(THF)k]n 5 as simple amido species. Complex [{PhC­(CH2)}­{PhCH­(CH3)}­NNa·TMEDA]∞ 6 was isolated as a result of a β-hydride elimination. A complex mixture of species was isolated when B-α-mba was reacted with potassium in the presence of TMEDA and PMDETA to give species [{PhCH­(CH3)}2­NK·(TMEDA)k]n 7a, [{PhC­(CH2)}­{PhCH­(CH3)}­NK·(TMEDA)k]n 7b, [{PhC­(CH2)­NH}­K·(TMEDA)k]n 7c, [{PhCH­(CH3)}2­NK·(PMDETA)k]n 8a, [{PhC­(CH2)}­{PhCH­(CH3)}­NK·(PMDETA)k]n 8b, and [{PhC­(CH2)­NH}­K·(PMDETA)k]n 8c. In both cases, the decomposition to form the potassium enamide species 7c and 8c was the more favorable process. The decomposition reaction of B-α-mba with nBuNa in the presence of PMDETA to give the sodium enamide [PhC­(CH2)­N­(H)­Na·PMDETA] 1 was investigated with GC-MS studies revealing the byproduct of this decomposition as styrene.