The BF_3OEt_2 catalyzed one-pot 1,3-dipolar cycloaddition reaction of benzylamines,isatins and dimethyl acetylenedicarboxylate in dry methylene dichloride afforded the functionalized dihydrospiro[indoline-3,2'-pyrroles]in moderate to good yields and with high diastereoselectivity.The reaction was accomplished by the tandem 1,3-dioplar cycloaddition of in situ generated azomethine ylide with acetylenedicarboxylate and the nucleophilic addition of pyrrole ring to second molecular acetylenedicarboxylate.
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