反应详情

To D/L-leucic acid (7.58 g, 57.36 mmol) in MeOH/H2O (9:1, 100 mL) was added a 20% solution of Cs2CO3 in water until the pH reached 7.0. The reaction mixture was concentrated in vacuo to dryness, DMF was added and concentrated in vacuo to dryness again. The solid was suspended in DMF (100 mL) at 0° C., 4-methoxybenzyl chloride (7.8 mL, 51.6 mmol) was added dropwise and the reaction mixture stirred overnight. The mixture was added to water and the product extracted with Et2O, dried over Na2SO4, concentrated in vacuo and purified by flash chromatography over silica gel (EtOAc/Hex, 2/8, then 3/7) to afford 4-methoxybenzyl 2-hydroxy-4-methylpentanoate.

1. concentrationThe reaction mixture was concentrated in vacuo to dryness, DMF
2. additionwas added
3. concentrationconcentrated in vacuo to dryness again
4. customwas suspended in DMF (100 mL) at 0° C.
5. extractionthe product extracted with Et2O
6. dry with materialdried over Na2SO4
7. concentrationconcentrated in vacuo
8. custompurified by flash chromatography over silica gel (EtOAc/Hex, 2/8