A Series of [3 + 2] Cycloaddition Products from the Reaction of Rhenium Oxo Complexes with Diphenyl Ketene

The reaction of rhenium (VII) trioxo complexes containing the ligand sets scorpionate, [HB(pz)3]ReO3 (6), [Ph−B(pz)3]ReO3 (7), and [{HC(pz)3}ReO3][ReO4] (8) and pyridine/pyridine-type ligands [(4,7-diphenyl-1,10-phen)(Br)ReO3] (12), [(4,4‘-di-tert-butyl-2,2‘-dipyridyl)(Cl)ReO3] (13), and [(py)2Re(Cl)O3] (4), with diphenyl ketene, has led to
the isolation of six novel [3 + 2] cycloaddition products. These air-stable solids 9−11 and 15−17 are the result of
[3 + 2] addition of the OReO motif across the ketene CC double bond. Five of the six [3 + 2] cycloaddition
products have been structurally characterized by single-crystal X-ray diffraction and in all cases by 13C NMR and
IR spectroscopies.