Reaction Steps
A solution of phenylsilane (PhSiH3) (0.385 μl, 3.12 μmol) in 1,3-dimethyl-2-imidazolidinone (DMI) (140 μl), and tetrakis(triphenylphosphine)palladium (0) (Pd(Ph3P)4) (1.80 mg, 1.56 μmol) were added to allyl ((2R)-3-(tert-butyldisulfanyl)-1-oxo-1-((4-((5S,8S,11S,14S,17S,20S,23S,26S,29S,32S)-5,23,32-tribenzyl-2-((tert-butyldisulfanyl)methyl)-11,17-diisobutyl-13,14,16,20,22,25,26,29-octamethyl-3,6,9,12,15,18,21,24,27,30,33-undecaoxo-1-oxa-4,7,10,13,16,19,22,25,28,31-decaazacyclotritriacontan-8-yl)butyl)amino)propan-2-yl)carbamate (*Phe-tBuSSlac-Phe-Lys(Alloc-Cys(StBu))-Leu-MeAla-MeLeu-Ala-MePhe-MeAla-Ala*, cyclized at two * sites) (Compound SP671) (2.5 mg, 1.56 μmol) at room temperature, and the reaction solution was stirred at 30° C. for 1 hour and 30 minutes. The reaction solution was purified by reverse-phase silica gel chromatography (0.1% aqueous formic acid/0.1% formic acid-acetonitrile solution) to afford (2R)-2-amino-3-(tert-butyldisulfanyl)-N-(4-((5S,8S,11S,14S,17S,20S,23S,26S,29S,32S)-5,23,32-tribenzyl-2-((tert-butyldisulfanyl)methyl)-11,17-diisobutyl-13,14,16,20,22,25,26,29-octamethyl-3,6,9,12,15,18,21,24,27,30,33-undecaoxo-1-oxa-4,7,10,13,16,19,22,25,28,31-decaazacyclotritriacontan-8-yl)butyl)propanamide (*Phe-tBuSSlac-Phe-Lys(H-Cys(StBu))-Leu-MeAla-MeLeu-Ala-MePhe-MeAla-Ala*, cyclized at two * sites) (Compound SP665) (2.60 mg, 88%).
