SYNTHESIS OF DISPIRO[1-BENZOTHIOPHENE-2,3'-PYRROLIDINE- 2',3''-INDOLINE]-2'',3-DIONES IN CYCLOADDITION REACTION

Abstract

The 1,3-dipolar cycloaddition of azomethine ylides derived from isatin and sarcosine to (Z)-2-(arylmethylidene)-1-benzothiophen-3(2H)-ones afforded novel dispiro[1-benzothiophene-2,3'-pyrrolidine-2',3''-indoline]-2'',3-diones in moderate yields. The structures of all the products were characterized by NMR, IR, HRMS together with X-ray crystallographic analysis. The reaction gives two diastereomeric products. This result is different from the cycloaddition of isatin, sarcosine, and other exocyclic olefins which generally afford only one
product.