4-Methyl-2-oxovaleric acid → Benzyl 4-methyl-2-oxopentanoate

Beteiligte Stoffe

Reaktionsschritte

With reference to reaction Scheme 2, a slurry of 25 g (0.164 mol) of the sodium salt of 4-methyl-2-oxopentanoic acid, sodium salt in anhydrous N,N-dimethylformamide (50 ml) containing 19.6 ml (0.164 mol) of benzyl bromide was agitated at room temperature for 4 days. The solvent was removed in vacuo. The residue was dissolved in 250 ml of hexane and washed with water (3×50 ml) and brine (50 ml). After drying over anhydrous magnesium sulfate, the solution was filtered and concentrated in vacuo to give 33.2 g (92% yield) of benzyl 4-methyl-2-oxopentanoate (1a) as a viscous, colorless oil. TLC: Rf 0.70 (ethyl acetate-hexane 1:4); 1H NMR(CDCl3) δ 0.94(d, 6H), 2.18(m, 1H), 2.71(d, 2H), 5.26(s, 2H), 7.37(m, 5H); 13C NMR (CDCl3) δ 22.5, 24.2, 48.1, 67.9, 128.7, 128.8, 128.9, 134.7, 161.3, 194.0.

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