Diisopropylamine → Methyl 7-oxospiro[5.6]dodecane-8-carboxylate

Beteiligte Stoffe

Reaktionsschritte

A solution of diisopropylamine (1.130 mL, 7.93 mmol) in THF (10 mL) was treated with n-butyllithium (3.17 mL, 7.93 mmol) at −78° C., and the reaction was stirred at this temperature for 30 minutes. The above solution was then transferred via cannula into a solution of the product from Example 16A (1.1 g, 6.10 mmol) in THF (10 mL) at −78° C., and the resulting mixture was stirred at this temperature for 30 minutes. Dimethyl carbonate (5.14 mL, 61.0 mmol) was added, the cold bath was removed, and HMPA (1.062 mL, 6.10 mmol) was then added. The resulting mixture was stirred at ambient temperature for 16 hours. It was quenched with HCl (1N) and diluted with ether (200 mL), then the organic layer was separated, washed with H2O and brine, dried with MgSO4, and concentrated under reduced pressure. The residue was chromatographed on silica gel (95:5 hexane-EtOAc, eluant) to provide the title compound. 1H NMR (300 MHz, CDCl3) δ 3.88 (dd, J=11.87, 3.05 Hz, 1 H), 3.68 (s, 3 H), 2.06-2.16 (m, 1 H), 1.92-2.04 (m, 2 H), 1.59-1.90 (m, 5 H), 1.29-1.51 (m, 8 H), 0.98-1.16 (m, 2 H). MS (DCI+) m/z 239 (M+H).

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