Triethylamine → HCID 11109017, compound

Participants

Reaction Conditions

Reaction Steps

3-Methyl-3-phenylbutanoic acid (2, 1.00 g, 5.61 mmol) was dissolved in 70 mL of THF and cooled to −78° C. Triethylamine (1.17 mL, 8.42 mmol) and trimethylacetyl chloride (0.760 mL, 6.17 mmol) were added to the reaction flask producing a white solid. The resulting mixture was warmed to 0° C. for 1 h and then cooled back down to −78° C. In a second flask butyllithium (6.84 mL, 1.6 M in hexanes, 10.9 mmol) was added dropwise with vigorous stirring to a solution of (4S)-(−)-4-isopropyl-2-oxazolidinone (1.45 g, 11.2 mmol) at −78° C. in THF (60 mL) producing a white precipitate. The resulting suspension of the lithiated oxazolidinone was added via cannula to the reaction flask. Stirring was continued for 2 h, water was added and the reaction mixture was warmed to room temperature, whereupon it was extracted three times with diethyl ether. The combined organic extracts were dried over magnesium sulfate, and concentrated in vacuo. The product was purified by radial chromatography (4 mm plate, 3:7 diethyl ether-pet. ether) affording compound 3 as a clear, colourless oil in 84% yield (1.37 g, 4.74 mmol). 1H-NMR (400 MHz, CDCl3) 7.38 (d, 2H, J=7.3 Hz, H-19 and H-15) 7.28 (t, 2H, J=7.3 Hz, H-18 and H-16), 7.16 (t, 1H, J=7.3 Hz, H-17), 4.22-4.18 (m, 1H, H-4), 4.05 (dd, 1H, J=9.0 and 2.8 Hz, 1H-5), 4.00 (t, 1H, J=9.0 Hz, 1H-5), 3.38-3.30 (m, 2H, H-10), 2.16-2.12 (m, 1H, H-6), 1.48 (s, 3H, H-13 or H-12), 1.47 (s, 3H, H-13 or H-12), 0.79 (d, 3H, J=7.1 Hz, H-8 or H-7), 0.71 (d, 3H, J=6.9 Hz, H-8 or H-7); Mass spectrum (EI) 289 (8, M.+), 119 (100, [C9H11]+). Optical rotation obtained was [α]D25 +69.5 (c 1.16, CHCl3). Compound 3 was prepared according to D. A. Evans et al. (1988) Tetrahedron 44:5525.

Provenance & Evidence