Hydrochloric Acid → (+/-)-(4R*,5R*)-5-ethoxycarbonyl-1-methyl-4-[4-(1,1,2,2-tetramethyl-1-silapropoxy)-phenyl)pyrrolidin-2-one

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Reaction Steps

To a solution of (±)-(4R*,5R*)-5-ethoxycarbonyl-1-methyl-4-(4-hydroxyphenyl)pyrrolidin-2-one (Intermediate W, 0.400 g, 1.53 mmol) in anhyd. DMF (1.5 mL) was added imidazole (0.240 g, 3.05 mmol), followed by TBDMSCl (0.250 g, 1.68 mmol) and the mixture stirred at room temperature for 18 h. The resulting mixture was poured into a 0.5N HCl solution and extracted with EtOAc. The combined organic layers were dried (MgsO4) and concentrated under reduced pressure give a clear oil which was purified by flash chromatography (gradient from 67% to 100% EtOAc/hex) to yield (±)-(4R*,5R*)-5-ethoxycarbonyl-1-methyl-4-[4-(1,1,2,2-tetramethyl-1-silapropoxy)-phenyl)pyrrolidin-2-one (512 mg, 89%) as a light yellow oil: 1H NMR (DMSO-d6) δ 0.13 (s, 6H), 0.75 (t, J=7.0 Hz, 3H), 0.91 (s, 9H), 0.24-0.70 (m, 5H), 3.55-3.76 (m, 2H), 3.88 (q, J=9.1 Hz, 1H), 4.43 (d, J=9.1 Hz, 1H), 6.75-6.79 (m, 2H), 7.07-7.13 (m, 2H).

Provenance & Evidence