Sodium sulphate hydrate → (4R)-4-methylnonanoic acid

Participants

Reaction Conditions

Reaction Steps

(R)-2,6-Dimethylundec-2-ene 153 (10.03 g, 55.03 mmol) was dissolved in acetone (270 mL) and cooled to 0° C. Jones reagent (CrO3/H2SO4) (2.7 M, 120 mL) was added dropwise, and the reaction allowed to warm to room temperature over 18 hours. The reaction was poured on to water/Na2SO4 (200 mL), and the aqueous layer extracted with ethyl acetate (4×100 mL). The combined organics were dried over MgSO4, filtered and rotovapped to give an oil. The crude oil was dissolved in CH2Cl2 (400 mL) and cooled to −78° C. Ozone was bubbled into reaction until blue to remove traces of the impurity (6E)(3S)-3,7-dimethylocta-1,6-diene. Dimethylsulfide (5 mL) was added, and the reaction stirred at room temperature for 2 hours. The solvent was removed, and the crude material chromatographed on silica eluting with 20% EtOAc/hex to give oil. The oil was dissolved in ether (100 mL) and extracted with 10% NaOH (2×25 mL). The aqueous layers were combined and extracted with ether (50 mL). The aqueous layer was cooled to 0° C. and acidified with HCl. The acidic layer was extracted with EtOAc (3×100 mL), and the combined extracts dried over MgSO4, filtered and rotovapped to give 154 as an oil (6.86 g, 54%). 1H NMR (400 MHz, CDCl3) δ 2.40-2.25 (m, 4H), 1.70-1.62 (m, 2H), 1.47-1.11 (m, 8H), 0.87-0.84 (m, 6H); [α]D=−11.4 (c1 in CHCl3).

Provenance & Evidence