Ethyl diazoacetate → (2-Bocamino-2-methyl-propoxy)-acetic acid

Participants

Reaction Steps

A solution of 2 -tert-butoxycarbonylamino-2-methylpropanol (5.0 g, 26 mmol) and rhodium(II)acetate (90 mg) in 1,2-dichloroethane (500 ml) was heated to 80° C. Then ethyl diazoacetate (4.0 g, 35 mmol) was added over a period of 1 h, and the mixture was stirred at reflux for 3 h. Another portion of rhodium(II)acetate (90 mg) was added and the mixture was refluxed for another 5 h. The mixture was cooled overnight and saturated sodium bicarbonate (500 ml) was added, the phases were separated and the organic layer was washed with saturated sodium bicarbonate (2×200 ml), dried (magnesium sulfate) and concentrated in vacuo. The obtained product was dissolved in 1 M lithium hydroxide in methanol/water 3:1 (200 ml) and stirred overnight. The solvent was removed in vacuo, water was added (pH>9) and the mixture was washed with ether (200 ml). Then 1 M hydrochloric acid was added until pH<4 and the mixture was extracted with ethyl acetate (200 ml), dried (magnesium sulfate) and concentrated in vacuo to give 2.5 g of (2-tert-butoxycarbonylamino-2-methylpropoxy)acetic acid.

Provenance & Evidence