Acetamide → Isopropyl (2R,3S)-3-Acetamido-2-hydroxy-3-phenylpropanoate

Beteiligte Stoffe

Reaktionsschritte

Lithium hydroxide-hydrate (236 mg, 5.63 mmol) and osmium tetroxide (53 mg, 0.210 mmol) are dissolved in a minimal amount of water. To this is added t-butanol (8 ml) and (DHQ)2PHAL (205 mg, 0.263 mmol) and the reaction mixture is stirred for 10 minutes. Water (12 mil) is added and the reaction mixture is cooled in an ice bath to less than 4°. Acetamide (311 mg, 5.26 mmol), isopropyl cinnamate (I, 1.00 g, 5.26 mmol), and N-bromoacetamide (795 mg, 5.63 mmol) respectively are added to the reaction mixture. The mixture is stirred until complete as measured by HPLC. The reaction mixture is quenched with a small amount of sodium sulfite (50 mg) and allowed to warm to 20-25°. Ethyl acetate (5 ml) is added and the reaction mixture is stirred for 30 minutes. The phases are separated and the aqueous layer is extracted three times with ethyl acetate (30 ml). The organic layers are combined and washed three times with saline (30 ml). The organic layer is dried with sodium sulfate and filtered through a small amount of silica. The mixture is concentrated on a rotary evaporator and the product is recrystallized from ethyl acetate/hexane to give the title compound; mp=104-106°; HMR (300 MHz, CDCl3) 1.30, 2.00, 3.20, 4.78, 5.05, 5.55, 6.23 and 7.35 δ.

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