Evaluation of vinyl heteroarenes^a,b.

^aReaction conditions: benzaldehyde (1a, 0.4 mmol), hydrazine (0.48 mmol), vinyl heteroarene 3 (0.2 mmol), [Ru(p-cymene)Cl₂]₂ (2.5 mol%), ligand (5 mol%) and base (0.1 mmol) in THF (0.5 mL) at 80 °C for 12 h under N₂.

^bYields of isolated products based on 3.

^c0.1 mmol of 2,6-divinylpyridine was used.