Compound 70 Experimental

NH4OAc (4.53 g, 60.0 mmol, 40 equiv.) and NaCNBH₃ (707 mg, 11.25 mmol, 7.5 equiv.) were dissolved in MeOH (60 mL, 0.025 M) at ambient temperature in a sealed tube. Molecular sieves S44(3Å, 6.0 g) were then added to the solution. Subsequently, cyclized ketone 44 (492 mg, 1.50 mmol, 1.0 equiv.) was dissolved in THF (12.0 mL, 0.125 M) and added to the MeOH solution. The reaction mixture was degassed by bubbling with argon for 30 minutes and was then sealed in the reaction vessel. The sealed tube was placed in a sonicator and exposed to ultrasonic radiation for 18 hours. The reaction mixture was then filtered through a pad of celite and concentrated in vacuo. The crude reaction was then diluted with 2 N NaOH (100 mL) and extracted with EtOAc (3 x 100 mL). The combined organic extracts were washed with brine (50 mL), dried (MgSO4), and the solvent was removed in vacuo. The crude reaction was purified by flash column chromatography (silica gel, gradient from 3:1 to 1:1 hexanes:EtOAc) to give compound 70 (206 mg, 42%).3:1 to 1:1 hexanes:EtOAc) to give compound 70 (206 mg, 42%).