tert-Butyl mercaptan → (3S,5R,6S)-3-Allyl-1-((S)-2-(tert-butylthio)-1-cyclopropylethyl)-6-(4-chloro-3-fluorophenyl)-5-(3-chlorophenyl)-3-methylpiperidin-2-one

Participants

Reaction Conditions

Reaction Steps

2-Methyl-2-propanethiol (15.25 mL, 135 mmol, dried over activated 4 Å molecular sieves) was added to a solution of lithium bis(trimethylsilyl)amide in tetrahydrofuran (1.0 M, 135 mL, 135 mmol) at room temperature under argon in a 500 mL round-bottomed flask. The reaction mixture was heated to 60° C. After 30 minutes, a solution of (3S,5S,6R,8S)-8-allyl-5-(4-chloro-3-fluorophenyl)-6-(3-chlorophenyl)-3-cyclopropyl-8-methyl-2,3,5,6,7,8-hexahydrooxazolo[3,2-60 ]pyridin-4-ium 4-methylbenzenesulfonate (78 g, 123 mmol, Example 4, Step H) in anhydrous tetrahydrofuran (100 mL) was added via cannula. The reaction mixture was heated at 60° C. for 3 hours and then cooled to room temperature. The reaction mixture was quenched with water and extracted thrice with ethyl acetate. The organics were pooled, washed with brine, dried over magnesium sulfate, filtered and concentrated under a vacuum to provide a yellow foam. Purification by flash column chromatography (1.5 kg SiO2 column, gradient elution with 5% to 30% ethyl acetate in hexanes provided the title compound as an off-white foam.

Provenance & Evidence