From Borane to Borylene without Reduction: Ambiphilic Behavior of a Monovalent Silylisonitrile Boron Species.

Deprotonation of [(cAAC)BH2 (CN)] provided clean access to the stable boryl anion, [(cAAC)BH(CN)]- . Whereas the addition of soft electrophiles occurred at the nucleophilic boron center, harder silyl electrophiles added to the harder terminal cyano nitrogen. The resulting [(cAAC)BH(CNSiPh3 )] species behaved like a silylium boryl nucleophile as well as a neutral silylisonitrile borylene.