benzyl 2-(S)-[(tert-butoxycarbonyl)amino]-5-(trimethylsilyl)pent-4-ynoate
benzyl 5-{5'-[4''-(S)-benzyloxycarbonyl-4''-(tert-butoxycarbonyl)aminobut-1''-ynyl]-4'-iodopyridin-3'-yl}-2-(S)-[(tert-butoxycarbonyl)amino]pent-4-ynoate
benzyl 2-(S)-[(tert-butoxycarbonyl)amino]-5-(4',5'-diiodopyridin-3'-yl)pent-4-ynoate
(S)-2-((tert-butoxycarbonyl)amino)-4-pentynoic acid benzyl ester
4,4'-{4-[(S)-4-benzyloxycarbonyl-4-(tert-butoxycarbonyl)aminobutyl]pyridin-3,5-diyl}di[(S)-2-(tert-butoxycarbonyl)aminobutanoic acid]