Reluctance of 4-Chloro-5-metalla-1,3,2-diazaborolines To Undergo Metal Halide β-Elimination: An Opportunity for C-Functionalization of 1,3,2-Diazaborolines

N,N′-Bis(2,6-diisopropylphenyl)-1,4-diaza-1,3-butadiene reacts with dichlorophenylborane, affording the N,N′-bis(2,6-diisopropylphenyl)-2-phenyl-4-chloro-1,3,2-diazaboroline in a one-step process. The addition of lithium diisopropylamide gives rise to the 4-chloro-5-lithio-1,3,2-diazaboroline derivative, which cleanly undergoes a transmetalation reaction with TiCl4·2THF. Both the lithium and titanium complexes are stable with respect to metal chloride elimination and have been characterized by multinuclear NMR spectroscopy and by single-crystal X-ray diffraction studies. These findings open an avenue for the C-functionalization of 1,3,2-diazaborolines.