tert-butyl ((3S,7S,10R,11S,15S,18S,23aS)-11-hydroxy-18-isobutyl-10,15-diisopropyl-3-(4-methoxybenzyl)-2-methyl-1,4,8,13,16,19-hexaoxoicosahydro-15H-pyrrolo[1,2-g][1,13]dioxa[4,7,10,17]tetraazacyclohenicosin-7-yl)carbamate

(3S,4R)-allyl 4-amino-3-(tert-butyldimethylsiloxy)-5-methylhexanoate

(3S,4R)-allyl 4-[(S)-2-(tert-butoxycarbonylamino)-3-(tritylthio)propanamido]-3-(tert-butyldimethylsiloxy)-5-methylhexanoate

(3S,4R)-allyl 4-[(S)-2-amino-3-(tritylthio)propanamido]-3-(tert-butyldimethylsiloxy)-5-methylhexanoate