Submitted:
11 March 2026
Posted:
12 March 2026
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Abstract
cycloaddition of isatin ketonitrone 1,3-dipoles, generated from the condensation of various substituted isatins and arylhydroxylamines, with coumarins. The pentacyclic products bearing four consecutive stereocenters, including two quaternary carbon stereocenters fused in one ring structure, were smoothly acquired in moderate to high yields (22-98%) with high regio- (α and exo type) and diastereoselectivities (>20:1 dr). The synthesized compounds (>45 examples) were well characterized through different spectroscopic techniques, such as single crystal XRD, FTIR, NMR, and mass spectral analysis.
Keywords:
cycloaddition
; ketonitrone
; coumarin
; spirooindole
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