Asymmetric synthesis of functionalised pyrrolidines. Highly diastereoselective cyclisations mediated by sulfide and sulfoxide ligands

Silver(I)-catalysed cyclisation of sulfide 1b and sulfoxides 4 and 5 to give the corresponding 2-vinylpyrrolidines 2b, 6a and 7a, respectively proceeds with a high (up to 99% diastereoisomeric excess) level of diastereoselectivity; in all of these cases the sense of asymmetric induction observed has been shown to be the same.