Recently we disclosed a fundamentally new synthetic entry to ketenes based on isolable ketenyl anions such as IIa, which selectively reacted with various electrophiles to ketenes, but also enabled new transformations, such as through addition reactions across the ketenyl C-C bond. The ketenyl anions became accessible via a unique ligand exchange at the anionic carbon atom in α-metallated ylides (e.g. I), which underwent displacement of the phosphine ligand by carbon monoxide (Figure ). Shortly after our report, Liu and coworkers reported on a similar ligand exchange reaction at carbon to access ketenyl anions. Starting from the diazomethyl anion III they obtained ketenyl anion IIb via N2 by CO replacement. Both reactions impressively demonstrate the unique transition metal-like behavior of carbon in unusual (ylidic) bonding situations, which has been controversially discussed earlier based on computational studies of Frenking and co-workers. Figure . Reproted pathways to ketenyl anions from (A) metallated ylides or (B) metalla diazomethanes and (C) possible selectivities of the carbonylation of metalated ylides (18-c-6 = 18-crown-6, Dipp = 2,6-diisopropylphenyl).