(4S)-isobutyl-(5S)-((2R)-methoxycarbonyl-4-methylenecyclopentyl)-2,2-dimethyl-oxazolidine-3-carboxylic acid tert-butyl ester

tert-butyl (4S,5S)-4-isobutyl-5-((1R,2R)-2-(methoxycarbonyl)-4-(2-tosylhydrazineylidene)cyclopentyl)-2,2-dimethyloxazolidine-3-carboxylate