Methanol → 3R-hydroxymyristic acid methyl ester

Participants

Reaction Steps

A 500 ml autoclave was charged in a glove box (O2 content <1 ppm) with 46.2 g (180 mmol) of methyl 3-oxotetradecanoate, 131 ml of methanol and a solution of 2.1 mg (0.0036 mmol) of (R)-MeOBIPHEP and 1.08 mg (0.0018 mmol) of Ru2Cl4 (COD)2 (CH3CN) [Lit.: E. Singleton et al., S. Afr. Tydskr. Chem. 40, 183 (1987)] in 5 ml of dichloromethane. The hydrogenation was effected at 80° C. and 35 bar. The conversion amounted to >99% after 19 hours. The hydrogenation solution was concentrated at 50° C./17 mbar and the crystalline residue was taken up in 500 ml of diethyl ether. In order to separate the catalyst, the ethereal solution was filtered over 100 g of silica gel; e.e.=97.1%. After concentrating and drying the filtered ethereal phase there were obtained 45.8 g of methyl (R)-3-hydroxytetradecanoate as white crystals; e.e.=97.1%. After recrystallization from n-hexane there were obtained 41.9 g of pure methyl (R)-3-hydroxytetradecanoate; m.p. 42°-43° C.; e.e. 99.8%; [α]D20 : -16.4° (c=3.8, CCl4).

Provenance & Evidence