Ethyl diazoacetate → HCID 18648007, compound

Participants

Reaction Steps

Palladium(II) acetate (168 mg, 0.75 mmol) was dissolved in an ether solution (50 ml) of t-butyldimethylsilyl ether of (2R)-N-t-butoxycarbonyl-2-amino-3-butenol (3) (4.34 g, 15.0 mmol) and to this was added an ether solution (100 ml) of ethyl diazoacetate (17.1 g, 150 mmol) and palladium(II) acetate (168 mg, 0.75 mmol) over 3 hours. The insoluble material in the reaction mixture was filtered off and the filtrate was concentrated under reduced pressure to give an oily product. Purification of the product by column chromatography over silica gel (20% ether/hexane) afforded t-butyldimethylsilyl ether of (2R)-N-t-butoxycarbonyl-2-(ethoxycarbonylcyclopropyl)glycinol (4) as an oil (4.00 g, 87.9%). Compound (4) thus obtained was dissolved in ethanol (70 ml) and CSA (10 mg) was added to this solution then the mixture was stirred for 16 hours at room temperature. The solvent was removed under reduced pressure and the residue was subjected to medium pressure column chromatography over silica gel (50% ether/hexane) 932 mg of (2R,3S,4S)-N-t-butoxycarbonyl-2-(ethoxycarbonylcyclopropyl)glycinol (5), 175 mg of its stereoisomer (6) and 560 mg of a mixture of inseparable stereoisomer.

Provenance & Evidence