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 both like a silylium boryl nucleophile and a neutral silylisonitrile borylene.