Allyl bromide → (3R,5R,6S)-3-allyl-1-((S)-1-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methoxypiperidin-2-one

Participants

Reaction Conditions

Reaction Steps

A solution of (5R,6S)-1-((S)-1-((tert-butyldiphenylsilyl)oxy)butan-2-yl)-5-(3-chlorophenyl)-6-(4-chlorophenyl)-3-methoxypiperidin-2-one (495 mg, 0.749 mmol; Example 203, Step B) in THF (7.49 mL) was sparged with argon for 5 minutes and cooled to 0° C. 1.0 M lithiumdiisopropylamide solution in THF (1.461 mL, 1.461 mmol) was added dropwise. The internal temperature did not rise above 2° C. After 30 minutes, allyl bromide (0.194 mL, 2.247 mmol) was added. The cooling bath was replaced with a room temperature water bath. After 70 minutes, the mixture was quenched with sat. aq. NH4Cl solution and extracted with ethyl acetate. The organic layer was washed with sat. aq. NaCl solution, dried over Na2SO4 and concentrated. The residue was purified by flash chromatography on silica gel (40 g column, eluent: 5 to 30% ethyl acetate/hexanes) to afford the title compound as the more polar diastereomer.

Provenance & Evidence