tert-butyl (2S,4R)-2-ethynyl-4-hydroxypyrrolidine-1-carboxylate → (Z)-3-[(4-Acetyl-1H-pyrrol-2-yl)methylene]-1,3-dihydro-5-fluoro-4-[(2S,4R)-(4-hydroxy-pyrrolidin-2-yl)ethynyl]-2H-indol-2-one

Participants

Reaction Steps

Using Method C above, (3R,5S)-N-Boc-3-Hydroxy-5-ethynyl-pyrrolidine (240 mg, 1.13 mmol) (Example 99C above) was coupled with (Z)-3-[(4-acetyl-1H-pyrrol-2-yl)methylene]-1,3-dihydro-5-fluoro-4-iodo-2H-indol-2-one (150 mg, 0.38 mmol) (Example 90B) using (Ph3P)4Pd (43 mg, 0.04 mmol) and a catalytic amount of Cul in a mixture of DMF (5 mL) and Et3N (5 mL) as solvent at 80° C. for 5 hrs. Upon completion, the reaction mixture was diluted with EtOAc and extracted with H2O. The organic layer was dried over Na2SO4, concentrated and the residue was chromatographed on a silica gel column with a 0-100% EtOAc in hexanes gradient. The resulting intermediate was dissolved in 6 mL of a 50% trifluoroacetic acid in CH2Cl2 solution that contained 0.4 mL of H2O at 0° C. and stirred for 2 hrs. Upon completion, the solution was poured in ammonium hydroxide and extracted with a 5:1 (V/V) mixture of EtOAc and DMF. The organic layer was dried over Na2SO4 and concentrated. (Z)-3-[(4-Acetyl-1H-pyrrol-2-yl)methylene]-1,3-dihydro-5-fluoro-4-[(2S,4R)-(4-hydroxy-pyrrolidin-2-yl)ethynyl]-2H-indol-2-one was obtained after silica gel column chromatography with a 0-10% MeOH in CH2Cl2 gradient and trituration with CH2Cl2. (Yield 50 mg, 35%).

Provenance & Evidence