Reaction Steps
To a solution of 2-[3-ethyl-4-(2-nitrobenzenesulfonyl)-2-oxo-piperazin-1-yl]-3-naphthalen-2-yl-propionic acid methyl ester, 32, (5.3 g, 10. mmol) in anhydrous THF (10 mL) is added 1.0 M borane-tetrahydrofuran complex (32.0 mL) at −20° C. The reaction mixture is stirred at this temperature overnight. Methanol (3 mL) is added to the reaction mixture at −20° C. and the solution is allowed to stir for twenty minutes. Additional methanol (6 mL) is added and the reaction mixture is allowed to warm to room temperature. The solvent is removed in vacuo and the product is purified over silica (EtOAc/Hexane: 1:1) to afford 4.1 g (68% yield) of the desired product. 1H NMR (CDCl3, δ): 8.04–7.98m, (1H), 7.80–7.72 (m, 3H), 7.61–7.52 (m, 4H), 7.45–7.38 (m, 2H), 7.28 (d, J=9.6 Hz, 1H), 3.78 (t, J=6.0 Hz, 1H), 3.64 (d, J=11.0 Hz, 1H), 3.50 (s, 3H), 3.48 (t, J=7.2 Hz, 1H), 3.24–3.10 (m, 2H), 3.10–2.95 (m, 1H), 2.90 (t, J=11.0 Hz, 1H), 2.66 (d, J=2.4 Hz), 2.38–2.20 (m, 1H), 1.61–1.48 (m, 1H), 1.48–1.32 (m, 1H), 0.58 (t, J=9.6 Hz, 3H); ); 13C NMR, δ 171.7, 148.0, 135.9, 134.2, 133.7, 132.4, 132.0, 130.9, 128.0, 127.7, 127.6, 126.2, 125.6, 124.4, 69.0, 56.4, 53.8, 51.3, 47.0, 41.9, 35.2, 22.2, 10.7.
