Ammonium salt catalyzed multicomponent transformation: simple route to functionalized spirochromenes and spiroacridines

The combination of isatin or acenaphthoquinone, an activated methylene reagent, and 1,3-dicarbonyl compounds in the presence of catalytic ammonium chloride was found to be a suitable and efficient method for the synthesis of the biologically important spirooxindoles. (c) 2009 Elsevier Ltd. All rights reserved.