Following the procedure of Example 30, triethylamine (0.43 mL, 3.1 mmol), 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide (0.31 g, 1.6 mmol), N-hydroxybenzotriazole (0.22 g, 1.6 mmol), N-Boc-D-Thr(Bzl)-OH (0.42 g, 1.4 mmol), and 7,8,9,10-tetrahydro-6H-benzo[b]-cyclohepta[d]furan-2-ylamine (0.25 g, 1.2 mmol) provided tert-butyl {(1R,2R)-2-(benzyloxy)-1-[(7,8,9,10-tetrahydro-6H-benzo[b]cyclohepta[d]furan-2-ylamino)carbonyl]propyl}carbamate (0.11 g). MS (ESI) m/z 493 ([M+H]+); MS (ESI) m/z 491 ([M−H]−).
