(4S,5R)-5-[({(1S)-5-{[(benzyloxy)carbonyl]amino}-1-[(methylamino)carbonyl]pentyl}amino)carbonyl]-4-(tert-butoxycarbonyl)-7-methyloctanoic acid

4-benzyl 1-tert-butyl (2S,3R)-2-(3-hydroxypropyl)-3-isobutylbutanedioate

4-benzyl 1-tert-butyl (2S,3R)-2-allyl-3-isobutylbutanedioate

(2R)-3-(tert-butoxycarbonyl)-2-isobutyl-5-hexenoic acid

(2R,3S)-3-(tert-butoxycarbonyl)-6-hydroxy-2-isobutylhexanoic acid