Synthesis and characterization of new (N→B) phenyl substituted[N-benzyliminodiacetate O,O′,N]boranes

Abstract

The synthesis of nine (N→B) phenyl substituted[N-benzyliminodiacetate-O,O’,N]boranes 3a-3i is reported herein. These compounds were characterized by 1H, 13C, 11B, HETCOR, NOESY, infrared spectroscopy, mass spectrometry and in the case of compounds 3d and 3g also by 19F NMR. All compounds exhibit a bicyclic structure due to the presence of an intramolecular N→B coordination bond. The structure of 4-chlorophenyl [N benzyliminodiacetate-O,O’,N]borane 3e was further established by a single crystal x-ray diffraction study. The correlation between δ(11B) of compounds 3a, 3d-3i and σHammett values shows that the strength of the N→B bond depends on the electronic factors of the substituent on the B-phenyl group.