Methanol → (2R)-2-cyclohexyl-2-hydroxyacetic acid

Participants

Reaction Steps

To a solution of 200 mL methanol were added 38.0 g of R-(−)-mandelic acid, 2.5 mL acetic acid, and 7.5 g rhodium on carbon (5%, Engelhard 5864). The mixture was sealed in an autoclave, purged with nitrogen, and then filled with hydrogen gas. Hydrogenation was carried out at room temperature for 8 hours at 1400 psi. The reaction mixture was then removed from the autoclave and filtered. The filtrate was concentrated and recrystallized from toluene. The colorless crystals were collected by filtration and dried under vacuum to give 19.8 g of (R)-(−)-2-cyclohexyl-2-hydroxyacetic acid (92.0% yield from 20.7 g R-(−)-mandelic acid). 1H NMR (DMSO-d6): δ (ppm) 3.71 (d, 1H), 1.69-1.52 (m, 6H), 1.16-1.09 (m, 5H). 13C NMR (DMSO-d6): δ (ppm) 175.27, 74.19, 41.15, 28.86, 26.74, 25.84, 25.76, 25.57. IR (KBr): ν (cm−1) 3442, 2935, 2854, 1716, 1452, 1280, 1261, 1232, 1112, 1099. Anal. Calcd. for C8H14O3: C, 60.74; H, 8.92. Found: C, 60.89; H, 8.90. mp 124-126° C. [α]D20=−12.0° (c=1.0, CH3OH).

Provenance & Evidence