1,1'-Carbonyldiimidazole → tert-butyl [(1R,2S)-2-ethenyl-1-({[1-(methoxymethyl)cyclopropyl]sulfonyl}carbamoyl)cyclopropyl]carbamate

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Reaction Steps

A solution of (1R,2S)-1-[(tert-butoxycarbonyl)amino]-2-ethenylcyclopropanecarboxylic acid (132 mg) in THF (3 mL) was added 1,1′-carbonyldiimidazole (283 mg). The mixture was stirred 4 hours at reflux. The mixture was cooled to room temperature and a solution of 1-(methoxymethyl)cyclopropanesulfonamide (125 mg; Li et al., 2006, Synlett 5:725) and DBU (0.438 mL) in THF (3 mL) was added via cannula. The mixture was stirred for 40 hours at room temperature. The reaction was quenched with 1N HCl and the mixture was extracted twice with ethyl acetate. The combined organic layers were washed with brine, dried over anhydrous magnesium sulfate, filtered and concentrated under reduced pressure. The resulting residue was purified by flash chromatography (ISCO) to give the desired product (120 mg). 1H NMR (400 MHz, CDCl3): 5.71-5.62 (m, 1H), 5.29 (d, 1H), 5.16 (d, 1H), 3.36 (s, 2H), 2.15 (dt, 1H), 1.89 (dd, 1H), 1.75-1.68 (m, 2H), 1.49 (s, 9H), 1.34-1.30 (m, 1H), 1.08-1.03 (m, 2H).

Provenance & Evidence