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

Participants

Reaction Steps

A solution of 2-t-butoxycarbonylamino-2-methylpropanol (5.0 g, 26.46 mmol) and rhodium(II)acetate (90 mg) in dichloroethane (500 mL) was heated to 80° C. Ethyldiazoacetate (4.0 g, 34.78 mmol) was slowly added over a period of 1 hr., and the mixture was stirred at reflux for 3 hr. Another 90 mg of rhodium(II)acetate was added and the mixture was refluxed for another 5 hr. The mixture was cooled overnight and 500 ml of saturated sodium bicarbonate was added, the yellow organic layer was separated and washed twice with saturated sodium bicarbonate (2×200 ml). The organic layer was dried over magnesium sulfate and concentrated in vacuo. The yellow oil was taken up in 200 ml of 1 M Lithium hydroxide in methanol:water (3:1) and stirred overnight. The solvent was removed in vacuo to a minimum and water was added (pH>9) and the mixture was washed with ether. Then 1 M hydrogen chloride was added until pH<4 and the mixture was extracted with ethyl acetate, dried over magnesium sulfate and concentrated in vacuo to give 2.5 g (38%) of (2-t-butoxycarbonylamino-2-methylpropoxy) acetic acid as a clear oil.

Provenance & Evidence