ИСТИНА

The seven-membered zirconacyclocumulene complexes represent a new class of compounds, perspective for synthesis and catalysis. Previously, we investigated the reactions of the seven-membered zirconacyclocumulene (1), synthesized by Buchwald et al. (J. Am. Chem. Soc., 1993, 115, 10394), with nitriles and acetylenes. Here we report on the interaction of complex 1 with carbonyl compounds. We have found that the reactions of 1 with benzophenone, 9-fluorenone, and Michler's ketone, afford nine-membered zirconacyclocumulenes (2) whose protolysis results in the formation of the corresponding [3]cumulene diols (3). Different picture was observed in the intereaction of 1 with benzil at 80°C. In this case, a ninemembered dioxazirconacycle (4) was formed. Under the same conditions, the interaction of 1 with acenaphthenequinone gave a binuclear zirconacycle (5) and octasubstituted cyclooctatetraene (6).