a (a) Fmoc-amino acid/BOP/HOBt/DIEA, 30 min; piperidine/NMP, 20 min; (b) Fmoc-Ahx/Boc-Abu-OH (19:1)/BOP/HOBt/DIEA, 30 min; piperidine/NMP, 20 min; (c) Fmoc-AA/Boc-AA(19:1)/BOP/HOBt/DIEA, 2 h; 20% piperidine in NMP for Val and Gln; (d) Fmoc-Ile/Boc-Ile/Boc-Abu-OH(19:1:1)/BOP/HOBt/DIEA, 2 h, 20% piperidine in NMP for Ile; and (e) TFA-TIS-H2O (95:2.5:2.5) overnight.