Organic Syntheses via Transition Metal Complexes, 61^[1]^. – Pyridines and Pyridinium Salts from (β‐Aminovinyl)carbene Complexes (MCr, W) and Alkynes via 4(1__H__)‐Pyridinylidene Complexes
Pyridines and pyridinium salts were obtained in good yields by the condensation of (β‐aminovinyl)carbene complexes with alkynes. The reaction of [(Z)‐β‐(monoalkylamino)vinyl]carbene complexes [ 4‐(monoalkylamino)‐1–metalla–1,3–dienes)] L__n__MC(OEt)CHCRNHR^1^ (Z)‐6a–f (R, R^1^Ph, Me, __i__Pr, __n__Bu, CH~2~Ph, CH~2~OMe) with alkynes R^2^CCH 7a–c (R^2^ n__Bu, Ph, CH~2~OMe) involves the highly regioselective formation of 4(1__H)‐pyridinylidene complexes . Protonation of 8 with HBF~4~ leads to pyridinium salts 13 by the regiospecific substitution of the metal moiety L__n__M by a proton. The reaction may conveniently be performed in a one–pot procedure. {[(Z)‐β‐(H~2~‐Amino)vinyl]carbene}chromium complexes, e.g. 14, react with alkynes to give pyridines, e.g. 15. The thermal decomposition of 6 yields enol ethers 11. A regiospecific formation of (E)‐11 is observed in the thermolysis of 6 in the presence of pyridine.