Isolation of a Bis(oxazol-2-ylidene)-Phenylborylene Adduct and its Reactivity as a Boron-Centered Nucleophile

An isolable phenylborylene species supported by two oxazol-2-ylidene ligands was synthesized and structurally characterized. Computational studies revealed the presence of lone-pair electrons on the boron atom in this molecule; therefore, there are eight electrons around the three-coordinate boron center. The nucleophilic property was confirmed by the reactions with trifluoromethanesulfonic acid and [(thf)Cr(CO)(5)], which gave the corresponding conjugate acid and a chromium-borylene complex, respectively.