Reaction Steps
Cbz-Phe (4-CH2NHBoc)-Leu-OMe 79 (282 mg, 508 μmol) was dissolved in MeOH. TFA (45 μl, 607 μmol, 1.2 equiv.) was added and the mixture was bubbled through with Ar for 20 minutes. 10% Pd/C was added (50 mg) and the flask was filled with an H2 atmosphere for 3 hours. The mixture was filtered over CELITE and concentrated. The residue was dissolved in DCM and sat. aq. NaHCO3 and the aqueous layer was extracted with DCM (3×). The organic layers were dried over Na2SO4 and concentrated to yield the title compound (221 mg, quant.), which was used without further purification. 1H NMR (400 MHz, CDCl3): δ ppm 7.67 (d, J=8.6 Hz, 1H), 7.22 (d, J=8.0 Hz, 2H), 7.17 (d, J=8.1 Hz, 2H), 5.11 (s, 1H), 4.61 (td, J=8.9, 5.0 Hz, 1H), 4.28 (d, J=5.6 Hz, 2H), 3.72 (s, 3H), 3.61 (dd, J=9.0, 4.0 Hz, 1H), 3.19 (dd, J=13.7, 3.9 Hz, 1H), 2.72 (dd, J=13.7, 9.0 Hz, 1H), 1.70-1.48 (m, 3H), 1.45 (s, 9H), 1.03-0.89 (m, 6H). 13C NMR (101 MHz, CDCl3): δ ppm 173.91, 173.25, 155.77, 137.47, 136.49, 129.35, 127.56, 79.21, 56.06, 52.03, 50.13, 44.07, 41.22, 40.26, 28.23, 24.64, 22.69, 21.68.
