N-Heterocyclic carbene-phosphino-picolines as precursors of anionic 'pincer' ligands with dearomatised pyridine backbones; transmetallation from potassium to chromium.

Deprotonation of the α-picolinyl-CH2 in the hybrid ligands R2P–NCNHC (–N = substituted 2-picoline, R = Cy, t-Bu; CNHC = N-heterocyclic carbene) (L(R)) with KN(SiMe3)2 in ether gave [KL(Cy)–H(ether)]2 featuring a dearomatised picoline backbone. Assisted by 18-crown-6, K+ dissociation afforded the Z- and E-isomers of [L(R)–H](−). Transmetallation of L(R)–H from KL(R)–H led to [CrCl(L(t-Bu)–H)].