Reaction Steps
To a solution of acid from Example 34 (1.0 g, 1.40 mmol) in THF (15 ml) at −78° C., Borane (2.79 ml, 2.79 mmol, 1M solution in THF) was added. The solution was stirred at −78° C. for 30 min and slowly warmed to room temperature for 2 h. TLC showed no more starting material (EtOAc/hexane 3:7). Water (10 ml) was added. The mixture was extracted with EtOAc (3×20 ml). The combined EtOAc layers were washed with saturated sodium bicarbonate, brine and dried over sodium sulfate. The solvent was removed and the residue was purified by flash column on silica gel, eluting with EtOAc/hexane (30:70) to give the title compound as a colorless solid. 1H NMR (CDCl3, 500 MHz): δ a mixture of 1:1 atopoisomers 7.89 (s, 1H), 7.73 (s, 1H), 7.72 (s, 2H), 7.70 (m, 1H), 7.59 (d, J=8.0 Hz, 1H), 7.49 (d, J=8.5 Hz, 0.5H), 7.47 (d, J=8.0 Hz, 0.5H), 7.39-7.36 (m, 2H), 7.32 (s, 1H), 7.25 (m 1.5H), 7.20 (d, J=2.0 Hz, 0.5H), 5.62 (d, J=8.0 Hz, 1H), 4.99 (d, J=15.0 Hz, 0.5H), 4.83 (d, J=16.0 Hz, 0.5H), 4.73 (s, 2H), 4.15 (s, 1H), 4.10 (d, J=16.0 Hz, 0.5H), 4.01 (d, J=15.5 Hz, 0.5H), 3.96 (m, 0.5H), 3.86 (m, 0.5H), 2.34 (s, 1.5H), 2.33 (s, 1.5H), 0.61 (d, J=6.5 Hz, 1.5H), 0.58 (d, J=6.5 Hz, 1.5H).
