Orthogonal Strapping of o-Haloaryl Ynones with Pyrazolones: A One-Pot, Domino Process toward Spiropyrazolones.

A new class of spiroannulated pyrazolone scaffolds have been assembled from diverse o-haloaryl ynones and β-bromoalkenyl ynones via base mediated, one-pot, metal free, orthogonal strapping (tethering) mediated by the recursive anion(s) derived from pyrazolones. These convenient, preparatively useful transformations proceed through either a tandem Michael addition-intramolecular SNAr reaction or a tandem Michael addition-intramolecular AdNE process to furnish a range of pharmacophoric, diverse, spiroannulated pyrazolones from readily accessible precursors.