反应详情

To a solution of 5.98 mg (11 mmol) of potassium hydroxide in water (75 mL) and tetrahydrofuran (75 mL) was added 3.34 mg (10 mmol) of methyl (2R)-2-(2,4-di-t-butylphenyloxy)propanate (17). The reaction mixture was allowed to stir overnight at room temperature. The reaction mixture was acidified to pH 2 with concentrated hydrochloric acid and the resulting solution was extracted with diethyl ether (3×200 mL). The combined extracts were washed with an aqueous saturated sodium chloride solution (1×300 mL) and dried (MgSO4). Filtration and concentration afforded a thick crude oil. Purification by precipitation from hexane at -78° C. afforded 2.65 g (83%) of (2R)-2-(2,4-di-t-butylphenyloxy)propanoic acid (18) as a white crystalline material: 1H NMR (CDCl3) δ1.29 (s, 9 H), 1.42 (s, 9 H), 1.68-1.70 (d, 3 H), 4.77-4.85 9q, 1 H), 6.58-6.61 (d, 1 H), 7.11-7.15 (d, 1 H), 7.34 (s, 1 H); 13C NMR (CDCl3) δ177.2, 153.5, 143.3, 137.3, 124.4, 123.3, 110.7, 71.4, 35.0, 34.3, 31.6, 30.0, 18.5.

1. extractionthe resulting solution was extracted with diethyl ether (3×200 mL)
2. washThe combined extracts were washed with an aqueous saturated sodium chloride solution (1×300 mL)
3. dry with materialdried (MgSO4)
4. filtrationFiltration and concentration
5. customafforded a thick crude oil
6. customPurification
7. customby precipitation from hexane at -78° C.