反应详情

To a scalemic mixture enriched in (1S,2R,4R)-2-ethyl-4-hydroxycyclopentanecarboxylic acid (2.56 g, 16.21 mmol) in DMF (10.81 mL) was added TBDMSCl (2.93 g, 19.45 mmol) and imidazole (2.76 g, 40.5 mmol). The reaction mixture was stirred at ambient temperature for about 2 days then extracted with pentane (3×25 mL). The combined pentane layers were washed with water (25 mL) and brine (25 mL), dried over anhydrous MgSO4, filtered and concd under reduced pressure. The residue was purified using silica gel chromatography eluting with 20-100% EtOAc in heptane give a scalemic mixture enriched in (1S,2R,4R)-4-(tert-butyldimethylsilyloxy)-2-ethylcyclopentanecarboxylic acid (1.13 g, 26%): LC/MS (Table 1, Method b) Rt=3.03 min; MS m/z: 273 (M+H)+.

1. extractionthen extracted with pentane (3×25 mL)
2. washThe combined pentane layers were washed with water (25 mL) and brine (25 mL)
3. dry with materialdried over anhydrous MgSO4
4. filtrationfiltered
5. customThe residue was purified
6. washeluting with 20-100% EtOAc in heptane
7. customgive a scalemic mixture