Chemo- and Diastereoselective Synthesis of Spirooxindole-pyrazolines and Pyrazolones via P(NMe<sub>2</sub>)<sub>3</sub>-Mediated Substrate-Controlled Annulations of Azoalkenes with α-Dicarbonyl Compounds
Yunfeng Du, Yuefei Liu, Hongyu Guo, Rongfang Liu, Rong Zhou
Abstract
-mediated substrate-controlled annulations of azoalkenes with α-dicarbonyl compounds are reported, where the azoalkenes serve as either four or five-atom synthons chemoselectively. The azoalkene participates in annulation with isatins as a four-atom synthon to furnish the spirooxindole-pyrazolines, whereas it functions as a novel five-atom synthon in annulation with aroylformates, thereby leading to chemo- and stereoselective formation of pyrazolones. The synthetic utilities of the annulations have been demonstrated, and a novel TEMPO-mediated decarbonylation reaction is unveiled.
Topics & Concepts
SynthonChemistryAnnulationPyrazolonesSubstrate (aquarium)StereoselectivityCombinatorial chemistryStereochemistryOrganic chemistryCatalysisOceanographyGeologyCatalytic C–H Functionalization MethodsSynthesis and Catalytic ReactionsCyclopropane Reaction Mechanisms