(2R)-5-Phenyl-2-methylpentanoic acid → (R)-(-)-ethyl 2-methyl-5-phenylpentanoate

Participants

Reaction Steps

(R)-(−)-Ethyl 2-methyl-5-phenylpentanoate was prepared from 20mc(i) (20.8 g) in the same manner (S)-(+)-ethyl 2-methyl-5-phenylpentanoate was prepared from 20mb(i) as described above. The residue was purified by silica gel chromatography. Elution with ethyl acetate-heptane (5:95 v/v) afforded the title compound (21.0 g, 88%) as a clear oil; TLC Rf 0.66 (solvent system: 15:85:1 v/v/v ethyl acetate-heptane-acetic acid); MS (ESI+) m/z 221.2 (M+H)+; 1H-NMR (CDCl3) δ 7.32-7.26 (m, 2H), 7.20-7.14 (m, 3H), 4.11 (q, J=7.32 Hz, 2H), 2.64-2.57 (m, 2H), 2.48-2.39 (m, 1H), 1.75-1.53 (m, 3H), 1.52-1.41 (m, 1H), 1.27-1.21 (m, 3H), 1.13 (d, J=6.96 Hz, 3H,); [α]Tλ=α/cl, [α]21.9D=−0.114/(0.01771 g/1.5 mL)(0.5)=−19.31° (c=1.18, CHCl3).

Provenance & Evidence