Lawesson's reagent → 6-Chloro-4'-(3-chlorophenyl)-2'-(5-fluoro-2-methylphenyl)-2,3-dihydro-1'-[(tert-butoxycarbonyl)methyl]-2-oxo-6'-thioxo spiro[indole-3,3'-piperidine] 1-methoxyethyl trimethylsilane

Participants

Reaction Conditions

Reaction Steps

The mixture of racemic (2′R, 3R, 4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(5-fluoro-2-methylphenyl)-2,3-dihydro-1′-[(tert-butoxycarbonyl)methyl]-2,6′-dioxo spiro[indole-3,3′-piperidine]-1-methoxyethyl trimethylsilane (1 g, 1.4 mmol) prepared in example 1e and 2,4-bis-(4-methoxyphenyl)-1,3-dithia-2,4-diphosphetane 2,4-disulfide (1.5 g, 3.75 mmol) (Aldrich) in toluene (20 mL) was heated at 120° C. for 0.5 h. The mixture was cooled to room temperature and then concentrated. The residue was purified by chromatography (EtOAc:hexanes=1:1) to give racemic (2′R, 3R, 4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(5-fluoro-2-methylphenyl)-2,3-dihydro-1′-[(tert-butoxycarbonyl)methyl]-2-oxo-6′-thioxo spiro[indole-3,3′-piperidine]-1-methoxyethyl trimethylsilane as a off white foam (Yield 1.0 g, 92%).

Provenance & Evidence