Water → (4R,5S)-(+)-4-Methyl-5-phenyl-2-oxazolidinone

Participants

Reaction Conditions

Reaction Steps

Lithium aluminium hydride (10.26 g) was added to a stirred solution of (4R,5S)-4-methyl-3-((2R)-2-methyl-4,4,4-trifluorobutyryl)-5-phenyl-2-oxazolidinone (28 g) in dry diethyl ether (200 ml) at -20° C. under an inert atmosphere, then the mixture was warmed to 0° C. After 2 h at 0° C., water (10.27 ml), 10% w/v sodium hydroxide (10.27 ml) and water (31 ml) were added, and the mixture was stirred 20 min. The salts were filtered and washed with distilled diethyl ether. The diethyl ether solution was dried (K2CO3) and diluted with pentane. This resulted in precipitation of recovered (4R,5S)-(+)-4-methyl-5-phenyl-2-oxazolidinone which was isolated by filtration. Concentration of the filtrate by distillation afforded several fractions. The first fractions (bath temperature to 60° C.) were pentane and diethyl ether; a second set of fractions (bath temperature 60° C. to 100° C.) was 12 g of a oil that was a 40:60 mixture of (R)-2-methyl-4,4,4-trifluorobutane-1ol (calculated as 4.8 g alcohol) and diethyl ether by NMR. Warming the remaining tarry residue (bath temperature 85° C.) under vacuum (13,330 Pa) afforded an additional 7.2 g of (R)-2-methyl-4,4,4-trifluorobutan-1ol (total yield, 12.0 g, 94%); partial NMR (300 MHz, CDCl3 -D2O shake): 1.06 (d, 3H, CH3), 1.41 (br t, 1H, OH), 1.86-2.07 (m, 2H, CH(CH3) plus one CF3CH2), 2.31-2.42 (m, 1H, one CF3CH2), 3.49 (dd, 1H, one CH2OH), 3.58 (dd, 1H, one CH2OH). f. (R)-2-(2-Methyl-4,4,4-trifluorobutyl)-1H-isoindol-1,3(2H)-dione

Provenance & Evidence