(2S,3R,4S)-3-methyl-2-(4-methyl-2,6,7-trioxabicyclo[2.2.2]oct-1-yl)-5-oxo-4-phenylselenenyl-pyrrolidine-1-carboxylic acid benzyl ester

(2S,3S)-2-(4-methyl-2,6,7-trioxa-bicyclo[2.2.2]oct-1-yl)-5-oxo-3-(4-chlorophenyl)-pyrrolidine-1-carboxylic acid benzyl ester

(2S,3S)-2-(4-methyl-2,6,7-trioxa-bicyclo[2.2.2]oct-1-yl)-5-oxo-3-(1-naphthyl)-pyrrolidine-1-carboxylic acid benzyl ester