Abstract
2,6‐Bis(pyrrol‐2‐yl)pyridine (4), 2‐(pyrrol‐2‐yl)‐6‐[2‐(1‐vinylpyrrol‐2‐yl)]pyridine (5), 2,6‐bis[2‐(1‐vinylpyrrol‐2‐yl)]pyridine (6), 2,6‐dimethyl‐3,5‐bis[2‐(1‐vinylpyrrol‐2‐yl)] pyridine (9), 3‐acetyl‐2,6‐dimethyl‐5‐[2‐(1‐vinylpyrrol‐2‐yl)]pyridine (10), and 2,6‐dimethyl‐3‐(pyrrol‐2‐yl)‐5‐[2‐(1‐vinylpyrrol‐2‐yl)]pyridine (11) have been synthesized from the oximes of the corresponding diacetylpyridines in a one‐pot procedure by treatment with acetylene in MOH/DMSO systems (M = Li, K) at 80–140 °C under pressures of 25–30 atm, thus illustrating the applicability and general character of the reaction for synthesis of diverse dipyrrole‐pyridine assemblies and their N‐vinyl and acetyl derivatives. A stable **4·DMSO complex with bifurcated NH···O···**HN bonding has been isolated and its X‐ray structure determined. Quantum chemical analysis at the B3LYP/6‐311G* level shows that the cis‐cis conformation of 4 is most stable, with the cis‐trans and trans‐trans forms accordingly less favorable by 3.2 and 7.8 kcal mol^–1^. Activation barriers of cis‐cis‐to‐cis‐trans and cis‐trans‐to‐trans‐trans dynamics are 8.3 and 9.5 kcal mol^–1^, respectively, which means that internal rotation of the pyrrole rings in 4 is essentially hindered. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)