6-(tert-butoxycarbonyl)-6-azaspiro[2.5]octane-5(S)-carboxylic acid benzyl ester → (S)-6-(tert-Butoxycarbonyl)-6-azaspiro[2.5]octane-5-carboxylic acid

Participants

Reaction Steps

To a solution of (S)-6-aza-spiro[2.5]octane-5,6-dicarboxylic acid 5-benzyl ester 6-tert-butyl ester (intermediate 16, 110 g, 0.32 mol, ee:66%) in anhydrous methanol (1 L) was added Pd/BaSO4 (50 g) under hydrogen, the reaction mixture was stirred at room temperature for overnight. The resulting mixture was filtered and the liquid phase was evaporated to give 68 g of (S)-6-aza-spiro[2.5]octane-5,6-dicarboxylic acid 6-tert-butyl ester (light white solid, yield:85%) which was recrystallized with PE/EtOAc (4:1) to give 38 g of (S)-6-aza-spiro[2.5]octane-5,6-dicarboxylic acid 6-tert-butyl ester.

Provenance & Evidence