Sodium bis(trimethylsilyl)amide → (2S,5R)-2-tert-Butyl-5-((S)-2-ethyl-pentyl)-3-methyl-4-oxo-tetrahydro-pyrimidine-1-carboxylic Acid Methyl Ester

Participants

Reaction Conditions

Reaction Steps

To a −78° C. stirred solution of (S)-2-tert-butyl-3-methyl-4-oxo-tetrahydro-pyrimidine-1-carboxylic acid methyl ester (1.04 g, 4.57 mmol) in dry THF (15 mL) was added NaHMDS (5.03 mL, 1.0 M in THF) dropwise. The reaction was stirred at −78° C. for 1 hour and then a solution of (S)-3-Iodomethyl-hexane (1.24 g, 5.48 mmol) in dry THF (5 mL) was added dropwise. The reaction was stirred at this temperature for 2 hours and than was placed in a −10° C. refrigerator overnight. The reaction was quenched with sat. NH4Cl (20 mL) and was allowed to warm to room temperature. The layers were separated and the aqueous layer was extracted with EtOAc (3×15 mL). The organic extracts were combined and washed with brine (2×15 mL). The organic phase was dried over MgSO4, filtered and concentrated under reduced pressure. The product was purified by chromatography using hexanes/EtOAc (10–>20%) to yield 0.185 g (12%) of pure product: 1H NMR (400 MHz, CD3OD) 8 ppm 0.9 (m, 6 H), 1.3 (m, 5 H), 1.4 (m, 3 H), 1.7 (m, 1 H), 2.5 (m, 1 H), 2.9 (d, J=6.6 Hz, 2 H). MS: M+1 (328).

Provenance & Evidence