Lithium tri-s-butylborohydride → (3S,5R,6S)-3-Allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-1-((2S,3S)-2-hydroxypentan-3-yl)-3-methylpiperidin-2-one

L-Selectride™ (1M in THF, 5.24 ml, 5.24 mmol) was added to a solution at −10° C. of (3S,5R,6S)-3-allyl-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methyl-1-((S)-2-oxopentan-3-yl)piperidin-2-one (Example 149, step A, 2 g, 4.36 mmol) in THF (29.1 ml) being careful to maintain the temperature below −7° C. The reaction was stirred for 40 min then quenched into an aqueous solution of Oxone™ (10.73 g, 17.45 mmol) in 60 mL water. It was noted that the temperature spiked up to 40° C. during the addition. The reaction was cooled to RT using a water/ice bath and stirred at RT for 1 h, then diluted with ethyl acetate. The layers were separated and the aq layer was extracted with ethyl acetate. The combined organics were washed with brine and dried over MgSO4, filtered and concentrated. The crude material was dried under high vacuum overnight. Purification by column chromatography using 10-20% acetone in hexanes afforded the title compound.