5-Azaspiro[2.4]heptane-5,6-dicarboxylic acid, 1,1-dibroMo-, 5-(1,1-diMethylethyl) 6-Methyl ester, (6S)- → (6S)-1,1-dibromo-5-(tert-butoxycarbonyl)-5-azaspiro[2.4]heptane-6-carboxylic acid

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Reaction Steps

To a mixture of (6S)-5-tert-butyl 6-methyl 1,1-dibromo-5-azaspiro[2.4]heptane-5,6-dicarboxylate (3.05 g, 7.39 mmol) in THF-MeOH-water (35 mL, 14 mL and 14 mL respectively) was added LiOH monohydrate (930 mg, 3 eq). The mixture was stirred at room temperature for 1.5 hr before being evaporated off. The aqueous residue was acidified with 1M HCl, extracted with dichloromethane (2×50 mL). The combined organic layers were washed with water and brine, dried (Na2SO4), filtered and evaporated to give the title compound (quantitative yield) as a light yellow solid. 1H NMR (500 MHz, CDCl3): 10.45 (br s, 1H), 4.65-4.45 (m, 1H), 3.99-3.86 (m, 1H), 3.53-3.31 (m, 1H), 2.87-1.95 (m, 2H), 1.86-1.73 (m, 2H), 1.49, 1.48 and 1.44 (3 s, 9H).

Provenance & Evidence