Synthesis of N-tosyl-3,3,4-trisubstituted pyrrolidine derivatives starting from the Baylis–Hillman adducts via radical cyclization

N-Tosyl-3,3-disubstituted-4-vinylpyrrolidine derivatives 3a–c were synthesized via radical cyclization from the modified Baylis–Hillman adducts 2. The required starting materials 2a–c were prepared in moderate yields from the Baylis–Hillman adducts in three steps: (i) acetylation of the Baylis–Hillman adducts, (ii) SN2′ reaction with tosylamide to prepare 1, and (iii) alkylation with 1,4-dibromo-2-butene.