Preparation of 1,5-Disubstituted Pyrrolidin-2-ones

1,5-Disubstituted pyrrolidin-2-ones 18a−g, 19a−h, and 20a−f were synthesized in good to excellent yields via the nucleophilic substitution of 5-(benzotriazol-1-yl)-1-substituted-pyrrolidin-2-ones 9 with allylsilanes, organozinc reagents, and phosphorus compounds. Compounds 9 and 5-(benzotriazol-2-yl)-1-substituted-pyrrolidin-2-one isomers 10 are readily prepared in total 70−84% yields from 2,5-dimethoxy-2,5-dihydrofuran (7), primary amines 8, and benzotriazole; 9 and 10 react identically with nucleophiles.