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A general and practical three-component regioselective 1,3-dipolar cycloaddition of 3-amino-oxindole-based azomethine ylides and coumarins has been developed. This reaction displayed good substrate tolerance and gave a diverse array of biologically relevant spiro[ox--i-ndole-pyrrolidine-dihydrocoumarin] derivatives bearing four contiguous stereocenters including one spiro quaternary center in moderate to high yields (up to 90%) with high diastereoselectivities (up to 15:1 dr). It is based on the application of carboxylic acid activated coumarins as dienophiles followed by a decarboxylation process. The possible mechanism of the 1,3-dipolar cycloaddition is proposed via an exo ′-transition state. Furthermore, this is the first example of decarboxylative-mediated regioselective 1,3-dipolar cycloaddition of 3-amino-oxindole-based azomethine ylides and coumarins. [ABSTRACT FROM AUTHOR]

A new method was developed for the facile one-pot multicomponent construction of heterocycle-fused spiro compounds containing chromanone and pyrrolidinyl spirooxindoles, two potential pharmacophores, in one molecule through a decarboxylative 1,3-dipolar [3 + 2] cycloaddition reaction of carboxylic acid group-activated chromones 1 with isatin-derivated azomethine ylides based on molecular hybridization strategy. A wide variety of products with three contiguous stereocenters including a spiro quaternary stereocenter were smoothly prepared with high efficiency (up to 87% yield and 20:1 diastereomeric ratio). This method could offer libraries of architecturally diverse and multiple pharmacore collections, potentially useful in medicinal chemistry. [ABSTRACT FROM AUTHOR]