反应详情

A mixture of 3.5 g of methyl (3R )-2-methyl-3-dodecanoyloxypentanoate, 12 ml of methanol and 0.5 ml of concentrated sulfuric acid was refluxed for 8 hours, and 20 ml of water was added thereto followed by ether extraction. The ether phase was dried over anhydrous sodium sulfate and ether was distilled away, and then the residue was distilled to give 0.6 g of methyl (3R)-2-methyl-3-hydroxypentanoate of the following formula, b.p. 52.5° C. (2.5 mm Hg), [α]D30 =-10.7° (C=0.61, CHCl3). ##STR97## This compound was converted to (+)-MTPA ester according to a procedure similar to Example 1-(5) and the optical purity determined by 1H-NMR was 95% ee. The NMR chart is shown in FIG. 4.

1. temperaturewas refluxed for 8 hours
2. extractionthereto followed by ether extraction
3. dry with materialThe ether phase was dried over anhydrous sodium sulfate and ether
4. distillationwas distilled away
5. distillationthe residue was distilled