Acetone → 4-Methylheptanoic acid, (-)-

Participants

Reaction Steps

To (R)-2,6-dimethyl-non-2-ene (20 g, 0.13 mol) in acetone (433 mL) was added a solution of CrO3 (39 g, 0.39 mol) in H2SO4 (33 mL)/H2O (146 mL) over 50 minutes. After 6 hours a further amount of CrO3 (26 g, 0.26 mol) in H2SO4 (22 mL)/H2O (100 mL) was added. After 12 hours the solution was diluted with brine and the solution extracted with ether. The combined organic phases were dried (MgSO4) and concentrated. Flash chromatography (gradient of 6:1 to 2:1 hexane/EtOAc) gave (R)-4-methyl-heptanoic acid as an oil. 12.1 g; 65%. MS, m/z (relative intensity): 143 [M−H, 100%]; 1H NMR (400 MHz; CDCl3) δ 2.35 (m, 2H), 1.6 (m, 1H), 1.4 (m, 1H), 1.3 (m, 4H), 1.1 (m, 1H), 0.85 (s, 6H).

Provenance & Evidence