反应详情

This half-ester R-3c (250 mg; 1.0 mmol) was dissolved in methanol (2 mL) and treated with potassium carbonate (276 mg; 2.0 mmol; 2 equiv.) and stirred overnight to completely consume 3c (tlc analysis). The reaction mixture was diluted with water (25 mL) and extracted with ether (3×10 mL). The combined extracts were dried (MgSO4) and concentrated to afford 118 mg (79%) of R-1c. All achiral properties of 1c are as reported above. The absolute configuration of 1c was not exhaustively proven, but was presumed to be R-(-) by analogy with the enzymatic results of 1a and 1b. 1H nmr analysis of the MTPA ester using an analogous procedure to that of Dale et al., J. Org. Chem., 1969, 34, 2543, indicated 54% ee for R-1c. [α]D20 -8.2° (c. 1.19, CH3OH).

1. customto completely consume 3c (tlc analysis)
2. additionThe reaction mixture was diluted with water (25 mL)
3. extractionextracted with ether (3×10 mL)
4. dry with materialThe combined extracts were dried (MgSO4)
5. concentrationconcentrated
6. customto afford 118 mg (79%) of R-1c