Methanol → racemic (2'R,3R, 4'S)-6-chloro-2',4'-bis(3-chlorophenyl)-2,3-dihydro-2,6'-dioxo spiro[indole-3,3'-piperidine]-1-carboxylic acid ethyl ester

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(3-chlorophenyl)-3-trimethylsilyoxy-2-aza-1,3-butadiene prepared in example 1b in toluene (20 mL) was added E/Z-6-chloro-3-(3-chloro-benzylidene)-2-oxo-2,3-dihydro-indole-1-carboxylic acid ethyl ester prepared in example 6b (0.3 g, 0.83 mmol). The reaction mixture was stirred under nitrogen in a sealed tube at 135° C. for 1 h. After the solution was cooled to room temperature, methanol (50 mL) was added, and then the mixture was concentrated. The residue was purified by chromatography (EtOAc:CH2Cl2=1:3) to give racemic (2′R,3R,4′S)-6-chloro-2′,4′-bis(3-chlorophenyl)-2,3-dihydro-2,6′-dioxospiro[indole-3,3′-piperidine]-1-carboxylic acid ethyl ester as a yellow oil (Yield 0.45 g, 100%).

Provenance & Evidence