Spirocyclopropanes from Intramolecular Cyclopropanation of Pyranopyrazoles and Pyranopyrimidine-diones and Lewis Acid Mediated (3 + 2) Cycloadditions of Spirocyclopropylpyrazolones.
A robust intramolecular cyclopropanation reaction was first performed on pyranopyrazole and pyranopyrimidine-dione derivatives to obtain spirocyclopropylpyrazolones and barbiturates, using iodosylbenzene (PhIO) or the combination of iodobenzene diacetate (PIDA)/molecular iodine (I2), under mild reaction conditions. Syntheses of functionally and stereochemically diversified, novel spiropyrazolone fused 2-iminothiophene and spiropyrazolone fused pyrroline scaffolds were also demonstrated via Lewis acid catalyzed highly diastereoselective (3 + 2) cycloaddition reactions of the synthesized spiro-cyclopropyl pyrazolones with phenyl isothiocyanate and benzonitrile, respectively.
Department of Chemistry, University of Calcutta , Kolkata-700009, India.
Prasun
P
Mukherjee
Department of Chemistry, University of Calcutta , Kolkata-700009, India.
Asish R
0000-0001-8900-550X
AR
Das