Zirconium Hydrazinediido Complexes Derived from Cyclic Hydrazines and Their Role in the Catalytic Synthesis of 1,7-Annulated Indoles
摘要:
Reaction of cyclic 1,1'-disubstituted hydrazines with the bis(dimethylamido)zirconium complex [Zr{(N-Xyl)(2)N-py} (NMe2)(2)] (1) in the presence of dmap yielded the hexacoordinate zirconium hydrazinediido complexes [Zr{(N-Xyl)(2)N-py}(=NNC9H10)(dmap)(2)] (2) and [Zr{(N-Xyl)(2)N-py} (=NNC12H8)(dmap)(2)] (3). Hydrazinediides are thought to be key intermediates in the zirconium-catalyzed reaction of cyclic 1,1'-disubstituted hydrazines and disubstituted alkynes to yield 1,7-annulated indoles. Their basic structural motif is found in 5-HT3 receptor antagonists such as Cilansetron.