Abstract (F 5 C 6) 2 BNMe 2 (1) was prepared and (F 3 C) 2 BNMe 2 (2) was resynthesized. The crystal structures of both compounds were determined. In contrast to 2, compound 1 does not react with diazomethanes under carbine insertion into the BN bond. In this way the known (F 3 C) 2 BCH (SiMe 3) NMe 2 (3) was resynthesized from 2 and its solid-state structure was determined. The electron densities of compounds 1, 2, and 3 and those of ...