One-Pot Synthesis of Dispiro[oxindole-3,3′-pyrrolidines] by Three-Component [3+2] Cycloadditions of<i>in situ</i>-Generated Azomethine Ylides with 3-Benzylidene-2,3-dihydro-1<i>H</i>-indol-2-ones
An efficient one‐pot, three‐component synthesis of novel dispiro[oxindole‐3,3′‐pyrrolidines] by 1,3‐dipolar cycloaddition of azomethine ylides, in situ generated by reaction of 1,2‐diones with sarcosine and subsequent decarboxylation, with a series of (E)‐3‐benzylidene‐2,3‐dihydro‐1H‐indol‐2‐ones is reported. Molecular complexity is generated in only one synthetic step. All reactions proceed with excellent