(2S,3R,4S)-2-(2,2-Dimethyl-propionyloxymethyl)-3-hydroxy-4-isopropenyl-1-(4-methoxy-benzyl)-4-methyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester
(2S,3R,4R)-4-Acetyl-3-hydroxy-2-((R)-1-hydroxy-2-methyl-propyl)-1-(4-methoxy-benzyl)-4-methyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester
(2S,3R,4R)-4-Acetyl-3-(tert-butyl-dimethyl-silanyloxy)-2-hydroxymethyl-1-(4-methoxy-benzyl)-4-methyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester
(2S,3R,4S)-3-(tert-Butyl-dimethyl-silanyloxy)-2-hydroxymethyl-4-isopropenyl-1-(4-methoxy-benzyl)-4-methyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester
(2R,3R,4R)-4-Acetyl-3-(tert-butyl-dimethyl-silanyloxy)-2-formyl-1-(4-methoxy-benzyl)-4-methyl-5-oxo-pyrrolidine-2-carboxylic acid methyl ester