(2R,3S,Z)-tert-butyl 4-ethylidene-2-(hydroxymethyl)-3-methylpyrrolidine-1-carboxylate

(2R,3S,Z)-1-(tert-butoxycarbonyl)-4-ethylidene-3-methylpyrrolidine-2-carboxylic acid

(2R,3S,Z)-tert-butyl 4-ethylidene-2-((S)-1-methoxy-4-methyl-1-oxopentan-2-ylcarbamoyl)-3-methylpyrrolidine-1-carboxylate

(S)-methyl 2-((2R,3S,Z)-1-((S)-2-benzamido-6-((Z)-2,3-bis(tert-butoxycarbonyl)guanidino)hexanoyl)-4-ethylidene-3-methylpyrrolidine-2-carboxamido)-4-methylpentanoate