3-Bromo-2-methyl-1-propene → 4-Benzyl-3-[2-(5-benzyloxy-4'-trifluoromethyl-biphenyl-3-yl)-4-methyl-pent-4-enoyl]-oxazolidin-2-one

Participants

Reaction Conditions

Reaction Steps

To a colorless solution of 4-benzyl-3-[2-(5-benzyloxy-4′-trifluoromethyl-biphenyl-3-yl)-acetyl]-oxazolidin-2-one from the previous step (6.0 g, 11.00 mmol) in dry THF (22 mL) at −78° C. was added sodium bis(trimethylsiyl)amide (NaHMDS) (1 M in THF solution, 12.11 mL, 12.11 mmol), drop-wise, maintaining the internal temperature below −75° C. The resulting red solution was stirred at −78° C. for 30 minutes. To this was added 3-bromo-2-methyl propene (4.44 mL, 44 mmol) maintaining the temperature below −75° C. When the addition was near completion, the reaction mixture turned green. At this point the dry-ice bath was quickly removed and replaced with water-ice bath, and the addition was completed. The reaction mixture was stirred at 0° C. for an additional 30 min and quenched with saturated aqueous NH4Cl solution. The system was diluted with EtOAC (100 mL) and the organic phase was washed with saturated aqueous NaHCO3 solution (3×50 mL) and dried (MgSO4). Solvent was removed in vacuo and the crude mixture was purified by ISCO silica gel column to yield 4-benzyl-3-[2-(5-benzyloxy-4′-trifluoromethyl-biphenyl-3-yl)-4-methyl-pent-4-enoyl]-oxazolidin-2-one (6.3 g, 95%).

Provenance & Evidence