Water → (5S)-N-((2S)-2-(3,5-di-t-butylphenyloxy)propanoyl)-5-ethenylpyrrolidin-2-one

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Reaction Conditions

Reaction Steps

To 60% sodium hydride (336 mg, 10 mmol) in toluene (20 mL) at 0° C. was added dropwise a solution of 5-vinylpyrrolidin-2-one (1.0 g, 9.0 mmol) in toluene (10 mL) over a 5 min period. The cooling bath was removed and the solution was allowed to warm to 25° C. to ensure complete generation of the anion. To the anion at 25° C. was added dropwise a solution of (2R)-2-(3,5-di-t-butylphenyloxy)propanoyl chloride (11, 3.20 g, 9.8 mmol) in toluene (10 mL) over a 5 min period. TLC indicated that the reaction was complete upon addition of the acid chloride (silica gel plates; hexane and ethyl acetate, 2:1). Water (60 mL) was added to the reaction mixture and the phases were separated. The aqueous phase was extracted with ethylene chloride (1×40 mL). The combined organic phases were washed with a saturated aqeous sodium bicarbonate solution (1×70 mL) and dried (MgSO4). Concentration and purification by flash chromatography on silica gel (EM silica gel 60, 0.040-0.063 partical size, 230-400 Mesh, column size: 6.5 cm diameter×18 cm length) using hexane and ethyl acetate (19:1) afforded 1.65 g (46%) of (5S)-N-((2S)-2-(3,5 -di-t-butylphenyloxy)propanoyl)-5-ethenylpyrrolidin-2-one (15a) as an oil: 1H NMR (CDCl3) δ1.20 (s, 18 H), 1.60-1.62 (d, 3 H), 1.92-2.04 (m, 1 H), 2.21-2.32 (m, 1 H), 2.52-2.80 (m, 2 H), 4.9-4.96 (q, 1 H), 5.11-5.21 (m, 2 H), 5.77-5.88 (m, 1 H), 5.98-6.04 (q, 1 H), 6.71 (s, 2 H), 7.00 (s, 1 H); 13C NMR (CDCl3) δ175.2, 172.7, 157.1, 152.1, 135.2, 115.9, 115.6, 109.6, 72.3, 58.0, 34.9, 31.6, 31.4, 24.4, 18.1; IR (neat) 2966 (vs), 1740 (vs), 1715 (vs), 1593 (s), 1380 (s), 1229 (vs), 706 (w) cm-1.

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