反应详情

Phenylmethyl 1-oxa-5-azaspiro[2.3]hexane-5-carboxylate (165 mg, 0.75 mmol), prepared using procedures similar to those described in Reference 3, in THF (1 mL) was added to anhydrous ammonia saturated in THF (10 mL) and the mixture was allowed to stir in a sealed vessel at room temperature over 24 hours. The solution was then concentrated and taken back into THF (1 mL) followed by addition of di-tert-butyldicarbonate (164 mg, 0.75 mmol) and stirred for one hour at room temperature. The mixture was then concentrated and the residue purified by silica gel flash chromatography using hexanes:ethyl acetate (1:1) as eluent to give phenylmethyl 3-[({[(1,1-dimethylethyl)oxy]carbonyl}amino)methyl]-3-hydroxyazetidine-1-carboxylate (16.5 mg, 7% yield) and unreacted epoxide (120 mg, 73% recovery). 1H-NMR (400 MHz, CDCl3): 7.34 (m, 5H), 5.10 (br, 1H), 5.09 (s, 2H), 4.68 (s, 1H), 3.90 (dd AB, 4H), 3.41 (d, 2H), 1.44 (s, 9H).

1. concentrationThe solution was then concentrated
2. stirringstirred for one hour at room temperature
3. concentrationThe mixture was then concentrated
4. customthe residue purified by silica gel flash chromatography