Rapid, chemoselective and facile synthesis of azines by hydrazine/I-2

We report the reaction of hydrazine hydrate with carbonyl compounds in the presence of molecular iodine at 0-10 degrees C, which affords symmetrical azines in excellent yields in 1 to 4 min without any adverse effect on other substituents. The reactions are rapid and chemoselective, afford excellent yields, and have high-purity products. The workup procedure is environmentally benign and does not require solvent extraction.