Reluctance of 4-chloro-5-metalla-1,3,2-diazaborolines to undergo metal halide beta-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 x 2 THF. 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.
UCR-CNRS Joint Research Chemistry Laboratory (UMI 2957), Department of Chemistry, University of California at Riverside, Riverside, California 92521-0403, USA.
Emrah
E
Giziroglu
Bruno
B
Donnadieu
Guy
G
Bertrand