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 (6.0 g, 11.00 mmol) in dry THF (22 mL) at −78° C. was added sodium hexamethyl disilazide (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 at near completion, the system turned to green. At this point the dry-ice bath was quickly removed and replaced with wet-ice bath and completed the addition. The reaction mixture was stirred further at 0° C. for 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