Highly regio- and stereoselective 1,3-dipolar cycloaddition of stabilised azomethine ylides to 3,3,3-trihalogeno-1-nitropropenes: synthesis of trihalomethylated spiro[indoline-3,2′-pyrrolidin]-2-ones and spiro[indoline-3,3′-pyrrolizin]-2-ones.

Reactions of 3,3,3-trihalogen-1-nitropropenes with N -alkyl-α-amino acids (sarcosine, proline) and isatins proceed regio- and diastereoselectively to give a wide range of trihalomethylated spiro[indoline-3,2′-pyrrolidin]-2-ones and spiro[indoline-3,3′-pyrrolizin]-2-ones in good yields as a result of a 1,3-dipolar cycloaddition of the intermediate stabilised azomethine ylide at the double bond of the nitroalkenes. [ABSTRACT FROM AUTHOR]