反应详情

A mixture of 2-methyl-1-methylthiocarbonyloxypropyl 2-methylpropanoate (2b) (125 g) and lipase from Candida rugosa (Sigma-Aldrich) (12.5 g) in pH 7.2 phosphate buffered saline (1 L) was stirred at room temperature. The reaction was monitored by 1H-NMR using the chiral solvating agent (R)-(−)-2,2,2-trifluoro-1-(9-anthryl)ethanol. The reaction was stirred overnight. The reaction mixture was then diluted with ether, and the ether layer separated and filtered through a pad of CELITE® 545 to remove the enzyme. The ether layer was washed with aqueous sodium bicarbonate (NaHCO3) (5 times) and brine, and dried over anhydrous sodium sulfate (Na2SO4). After rotary evaporation to remove the solvent, 30.4 g of the title compound (4) was obtained. 1H-NMR using a chiral solvating agent confirmed the presence of a single isomer. The absolute configuration was determined by derivatization to a compound having known stereochemistry. 1H-NMR (CDCl3): δ 0.96 (d, J=6.8 Hz, 6H), 1.16 (d, J=6.8 Hz, 3H), 1.17 (d, J=6.8 Hz, 3H), 1.98-2.07 (m, 1H), 2.32 (s, 3H), 2.56 (septet, J=7.2 Hz, 1H), 6.67 (d, J=5.6 Hz, 1H) ppm.

1. stirringThe reaction was stirred overnight
2. customthe ether layer separated
3. filtrationfiltered through a pad of CELITE® 545
4. customto remove the enzyme
5. washThe ether layer was washed with aqueous sodium bicarbonate (NaHCO3) (5 times) and brine
6. dry with materialdried over anhydrous sodium sulfate (Na2SO4)
7. customAfter rotary evaporation
8. customto remove the solvent