(3R,4S,5R,1'S)-4-acetoxy-5-(1'-acetoxy-2'-methylpropyl)-3-methylpyrrolidin-2-one-5-carboxylic acid

(3R,4S,5R,1'S)-4-acetoxy-5-(1'-acetoxy-2'-methylpropyl)-3-methyl-5-(triethylsilyloxymethyl)pyrrolidin-2-one

(3R,4S,5R,1'S)-4-hydroxy-5-(hydroxymethyl)-5-(1'-hydroxy-2'-methylpropyl)-3-methylpyrrolidin-2-one

(4aS,7R,7aS)-tetrahydro-4a-(hydroxymethyl)-2,2,7-trimethyl[1,3]dioxino[5,4-b]pyrrol-6(4H)-one

(3R,4S)-4-hydroxy-3,8,8-trimethyl-7,9-dioxa-1-azaspiro[4.5]decan-2-one