Intramolecular C-N bond activation by a transient boryl anion.

Using a flexible diamido framework, a bulky boron bromide has been prepared as a precusor to a boryl anion with an extremely wide N-B-N angle. Reduction of the compound with lithium metal resulted in intramolecular C-N bond activation and migration of an aryl group onto the boron centre. Reaction of the boron bromide with K[FeCp(CO) 2 ] resulted in nucleophilic reactivity of a carbonyl oxygen and the cooperative activation of CO.