Efficient Protocol for the Synthesis of Novel Spiro[acenaphthylene-1,2′-pyrrolidin]-2-one Compounds

An efficient catalyst-free synthesis of 3′-benzoyl-4′,5′-diphenyl-2H-spiro[acenaphthylene-1,2′-pyrrolidin]-2-one derivatives via one-pot 1,3-dipolar cycloaddition of acenaphthenequinone, arylmethyl amines, and chalcones with high regioselectivity is described. The structure of the cycloadducts were characterized by infrared, high-resolution mass spectrometry (electrospray ionization), ¹H NMR, and ¹³C NMR spectra, and the structure of 4a was confirmed using x-ray single-crystal structure analysis.