Azobisisobutyronitrile → (6S)-5-[(tert-butoxy)carbonyl]-5-azaspiro[2.4]heptane-6-carboxylic acid

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Reaction Conditions

Reaction Steps

To a degassed solution of (6S)-1,1-dibromo-5-(tert-butoxycarbonyl)-5-azaspiro[2.4]heptane-6-carboxylic acid (580 mg, 1.45 mmol) in toluene (6 mL) was added the tris(trimethylsilyl)silane (1.35 mL, 4.36 mmol, 3.0 eq) and AIBN (24 mg, 0.145 mmol, 0.1 eq). The solution was heated at 110° C. for 3 hours. Another batch of tris(trimethylsilyl)silane (0.45 mL 1.45 mmol, 1.0 eq) and AIBN (10 mg) was added. The solution was heated at 110° C. for 2 more hours. A third batch of tris(trimethylsilyl)silane (0.45 mL 1.45 mmol, 1.0 eq) and AIBN (10 mg) was added. The solution was heated at 110° C. for 2 more hours. After being allowed to cool down, the solution was diluted with EtOAc (5 mL). This organic phase was extracted with aqueous K2CO3 (1 M, 10 mL×3). The combined aqueous extractions were cooled (ice/water) and acidified to pH 2 with concentrated HCl. This acidified aqueous phase was extracted with EtOAc (×3), dried (Na2SO4), filtered and evaporated. The residue was dried under vacuum to afford the desired compound as colorless oil (135 mg, 39%).

Provenance & Evidence