Z-6-chloro-3-(3-chloro-benzylidene)-2-oxo-2,3-dihydro-indole-1-carboxylic acid tert-butyl ester → racemic (2'R,3R,4'S)-6-chloro-4'-(3-chlorophenyl)-2'-(3-iodophenyl)spiro[3H-indole-3,3'-piperidine]-2,6'(1H)-dione

Participants

Reaction Conditions

Reaction Steps

To a solution of 1-(3-iodophenyl)-3-trimethylsilyoxy-2-aza-1,3-butadiene prepared in example 192a (1.2 g, 3.5 mmol) in toluene (40 mL) was added E/Z-6-chloro-3-(3-chlorobenzylidene)-2-oxo-2,3-dihydro-indole-1-carboxylic acid tert-butyl ester prepared in Example 24a (0.5 g, 1.28 mmol). The reaction mixture was stirred under nitrogen in a sealed tube at 140° C. for 1 h. After the solution was cooled to room temperature and concentrated. The residue was dissolved in dichloromethane (20 mL) and trifluoroactic acid (10 mL) was added. After the reaction mixture was stirred at room temperature for 0.5 h, the mixture was concentrated. The residue was partitioned between saturated NaHCO3 solution and ethyl acetate. The aqueous layer was extracted with ethyl acetate. The combined organic layer was dried over Na2SO4 and concentrated. The residue was purified by chromatography (EtOAc:CH2Cl2=1:3 then 1:2) to give racemic (2′R,3R,4′S)-6-chloro-4′-(3-chlorophenyl)-2′-(3-iodophenyl)spiro[3H-indole-3,3′-piperidine]-2,6′(1H)-dione as a white solid (Yield 0.56 g, 77%).

Provenance & Evidence