How is 4-Isobutylpyrrolidin-2-one (CAS: 61312-87-6) typically synthesized?

4-Isobutylpyrrolidin-2-one is commonly synthesized via a reaction between 2-chloro-4-isobutylpyrrole and potassium hydroxide in an aprotic solvent like dimethyl sulfoxide (DMSO). This method provides good yield and selectivity, with the reaction occurring under mild conditions. Other methods include the Wittig reaction involving isobutyl chlorophosphite and 2-pyrrolidonium bromide, which also yields high purity and selectivity.