Diisopropylamine → Methyl 6-oxospiro[4.5]decane-7-carboxylate

Participants

Reaction Conditions

Reaction Steps

A solution of diisopropylamine (5.97 mL, 41.9 mmol) in ether (30 mL) was cooled to −78° C. and then was treated slowly with n-butyllithium (16.75 mL, 41.9 mmol). The mixture was stirred at −78° C. for 30 minutes; then this solution was transferred via cannula into a −78° C. solution of Example 10A (4.25 g, 27.9 mmol) in ether (30 mL). The mixture was stirred at this temperature for 30 minutes and then was treated with dimethyl carbonate (23.50 mL, 279 mmol). The resulting mixture was warmed to ambient temperature and stirred for 16 hours. The mixture was quenched with saturated ammonium chloride and diluted with ether (100 mL); then the layers were separated. The aqueous layer was extracted with additional ether, then the organic layers were combined, dried with magnesium sulfate, and concentrated under reduced pressure. The residue was chromatographed on silica gel (100% hexane to 85:15 ethyl acetate/hexanes, eluant) to provide the title product. 1H NMR (300 MHz, CDCl3) δ 12.40-12.42 (m, 1H), 3.72-3.76 (m, 3H), 2.18-2.26 (m, 2H), 2.00-2.12 (m, 2H), 1.74-1.86 (m, 2H), 1.57-1.62 (m, 2H), 1.54-1.57 (m, 2H), 1.35-1.48 (m, 4H); MS (DCI+) m/z 211 (M+H)+.

Provenance & Evidence