Methyl iodide → Methyl 2-((3S,5R,6S)-1-((S)-1-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-2-oxopiperidin-3-yl)propanoate

Participants

Reaction Conditions

Reaction Steps

Methyl 2-((3S,5R,6S)-1-((S)-1-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-2-oxopiperidin-3-yl)acetate (Example 127, Step C) was azetroped with toluene 3× and then dissolved in THF (14 mL) under Ar and the mixture was cooled to −78° C. HMPA (236 μL, 1.356 mmol) and LHMDS (1.0M in THF) (1356 μL, 1.356 mmol) were added under Ar at −78° C. The mixture was stirred at −78° C. for 30 min. The mixture color turned light yellow. Then iodomethane (110 μL, 1.763 mmol) was added and the reaction mixture was allowed to slowly warm to room temperature. The mixture was quenched with sat. NH4Cl and the layers were separated. The combined organic layers were dried over Na2SO4 and concentrated under reduced pressure. The residue was purified by flash chromatography on silica gel (2×50 g stacked VersaPak I-style, Spherical, Supelco, Bellenfonte, Pa.; eluent: 20 to 30% MtBE in hexanes) to give the title compound as the less polar, major diastereomer. The retention time of the less polar diastereomer is 0.871 min (80-100% MeCN +0.1% TFA in water +0.1% TFA, over 1 minute). The retention time of the more polar diastereomer is 0.841 min (80 to 100% MeCN +0.1% TFA in water +0.1% TFA, over 1 minute).

Provenance & Evidence