反应详情

A 500 ml steel autoclave was loaded in a glove box (O2 -content less than 1 ppm) with 2.6 g (20 mmol) of itaconic acid, 150 ml of toluene, 50 ml of methanol, 2.02 g (20 mmol) of triethylamine, 36.0 mg (0.0886 mmol) of [Rh(COD)2 ]BF4, 49 mg (0.0886 mmol) of BPPM and 31.5 mg (0.0886 mmol) of tetrabutylammonium trifluoroacetate. the hydrogenation was carried out at a constant pressure of 6 bar of H2, at 30° C. and with intensive stirring. After a total hydrogenation time of 3 hours the reaction solution was evaporated and the residue was dissolved in 40 ml of 2N sodium hydroxide solution. The aqueous phase was washed with toluene, adjusted to pH 2 with conc. hydrochloric acid, saturated with NaCl and extracted with 3×100 ml of ether. The combined ether phases were dried over Na2SO4 and evaporated. There were obtained 2.4 g (92.3%) of methylsuccinic acid as white crystals. M.p. 111°-112° C. [α]D20 =-16.2° (c=5, EtOH). Optical purity 95.4%.

1. customwas carried out at a constant pressure of 6 bar of H2, at 30° C. and with intensive stirring
2. customAfter a total hydrogenation time of 3 hours the reaction solution was evaporated
3. dissolutionthe residue was dissolved in 40 ml of 2N sodium hydroxide solution
4. washThe aqueous phase was washed with toluene
5. extractionextracted with 3×100 ml of ether
6. dry with materialThe combined ether phases were dried over Na2SO4
7. customevaporated