(1R,2S,5S)-6-oxa-3-aza-bicyclo[3.1.0]hexane-2,3-dicarboxylic acid 2-benzyl ester 3-tert-butyl ester → (1R,2S,5S)-3-(tert-butoxycarbonyl)-6-oxa-3-azabicyclo[3.1.0]hexane-2-carboxylic acid

Participants

Reaction Steps

A solution (1R,2S,5S)-6-oxa-3-aza-bicyclo[3.1.0]hexane-2,3-dicarboxylic acid 2-benzyl ester 3-tert-butyl ester (2.62 g, 8.21 mmol) in ethyl acetate (32 mL) was hydrogenated under H2 with palladium hydroxide on carbon (1.15 g, 8.21 mmol) for 1 night. The reaction mixture was filtered over a glass fiber filter, quenched with Na2CO3 saturated aqueous solution and was extracted twice with EtOAc. The aqueous layer was acidified with HCl 1N to pH=2 and extracted 4 times with ethyl acetate, washed with brine, dried over Na2SO4, filtered and concentrated to give the desired material which was used in the next step without further purification. MS (UPLC): 230 [M+H]+, 228 [M−H]−.

Provenance & Evidence