Potassium Carbonate → 5-{5-[4-(1,3-Dioxo-1,3-dihydro-isoindol-2-yl)-butyl]-pyridin-2-yl}-pentanoic acid ethyl ester

Participants

Reaction Steps

To a stirred solution of 5-5 (4.23 g, 21 mmol) in degassed THF (20 mL) at 0° C. was added dropwise a solution of 9-BBN (50.4 mL of 0.5 M in THF, 25.2 mmol) and the mixture stirred for 18 hours at ambient temperature. K2CO3 (5.0 g, 35.8 mmol) and 5-2 (5.0 g, 17.4 mmol) were added, followed by a premixed and aged (70° C. for 30 min) suspension of Pd(OAc)2 (0.54 g, 2.4 mmol) and DPPF (1.45 g, 2.6 mmol) in degassed DMF (20 mL). The resulting mixture was stirred for 18 hours at 70° C., cooled, diluted with ethyl acetate, washed with water and brine, dried over MgSO4, and concentrated. To the stirring residue dissolved in THF (200 mL) was added water (75 mL) and NaHCO3 (16.5 g) and after 10 minutes, NaBO3.H2O (24 g). After vigorous stirring for 30 minutes, the mixture was diluted with ethyl acetate, washed with water and brine, dried over MgSO4, and concentrated to an oil. The residue was chromatographed on silica gel (20–40% EtOAc/hexane) to give 5-6 as a yellow solid.

Provenance & Evidence