benzyl (2S,3R)-4-((1S,3R)-3-(allyloxy)-6-methoxy-2,3-dihydro-1H-inden-1-ylamino)-3-hydroxy-1-phenylbutan-2-ylcarbamate → (2R,3S)-1-((1S,3R)-3-(allyloxy)-6-methoxy-2,3-dihydro-1H-inden-1-ylamino)-3-amino-4-phenylbutan-2-ol

Step V (2): A mixture of benzyl (2S,3R)-4-((1S,3R)-3-(allyloxy)-6-methoxy-2,3-dihydro-1H-inden-1-ylamino)-3-hydroxy-1-phenylbutan-2-ylcarbamate (700 mg, 1.36 mmol, from step N(1)), Ba(OH)2.H2O (1.46 g, 7.72 mmol), and DME/H2O (18 mL/12 mL) was heated at 110° C. in a sealed tube. After 16 h, cooled to rt, filtered of solid. Rinsed the vessel and filtercake with fresh DME and concentrated the filtrate in vacuo. The crude product was purified by silica-gel column chromatography (1-20% MeOH (containing 0.1% triethylamine)/chloroform, linear gradient) to provide 255 mg (49% yield) of the title compound. LC-MS (M+H)=383.0; HRMS (M+H)+=383.2332; [α]D +29.84 (c=6.43 mg/mL, methanol); 1H NMR (500 MHz, CDCl3) δ ppm 1.67 (d, 4H) 1.97 (d, J=13.43 Hz, 1H) 2.43-2.54 (m, 1H) 2.60-2.71 (m, 1H) 2.81 (dd, J=11.90, 8.55 Hz, 1H) 2.90-3.05 (m, 2H) 3.10-3.18 (m, 1H) 3.47 (s, 1H) 3.57 (s, 1H) 3.81 (s, 3H) 4.02-4.16 (m, 2H) 4.77 (dd, J=6.10, 3.97 Hz, 1H) 5.18 (dd, J=10.38, 1.53 Hz, 1H) 5.31 (dd, J=17.24, 1.68 Hz, 1H) 5.96 (dd, 1H) 6.85 (dd, J=8.24, 2.44 Hz, 1H) 6.95 (d, J=2.14 Hz, 1H) 7.15-7.35 (m, 6H).