“…[3,[19][20][21][22] Nevertheless during the last 20 years, besides "(C 6 H 11 ) 3 PBH 2 Li" as intermediate, [23,24] some examples for nucleophilic boron species have been described (Scheme 1), which are fully characterized and have found use in organic synthesis. [3,4] Herein we describe an unprecedented dianion in the salts M 2 [B(CN) 3 ] (M = Li, Na, K), which contains nucleophilic boron in the formal oxidation state + 1. This tricyanoborate anion was obtained by reductive B À C bond fission in [B(CN) 4 ]…”