反应详情

The product from Example 4 (25.0 0.112 mol, 97% diastereomeric excess), 1,4-dioxane (50 mL), and 4M H2SO4 (100 mL) were refluxed for 8 hours. The resulting solution was extracted with heptane (3×150 mL). The combined organic extracts were concentrated to afford the title compound (97% enantiomeric excess). The enantiomeric excess of the carboxylic acid was determined by chiral gas chromatography (GC) performed on a Hewlett-Packard 5890 Series gas chromatograph with a flame ionization detector (250° C.), and split mode capillary injection system (ratio 30:1), using a Chiraldex GTA column (30 m×0.25 mm, lot 06847 Serial # G0112-15); 1.0 μL injection volume, 250° C. injection temperature, helium carrier gas at 20 psi, oven temperature 160° C. isothermal, retention time of 9.02 minutes.

1. extractionThe resulting solution was extracted with heptane (3×150 mL)
2. concentrationThe combined organic extracts were concentrated