反应详情

To a solution of (S)-2-(diphenyl-trimethylsilanyloxymethyl)-pyrrolidine (417.0 mg, 1.3 mmol, 10 mol %) in acetonitrile (26 mL) at room temperature was added 1-propanal (2.6 mL, 38.4 mmol, 3.0 equiv) and 1-furan-2-yl-meth-(E)-ylidene]-carbamic acid tert-butyl ester (2.5 g, 12.8 mmol). After stirring at room temperature for 12 hours, the reaction mixture was quenched with water (20 mL) and extracted with EtOAc (3×30 mL). The organic layer was dried over Na2SO4, filtered and concentrated in vacuo. The crude residue was purified by column chromatography on silica gel (EtOAc/heptane) to give ((1S,2R)-1-furan-2-yl-2-methyl-3-oxo-propyl)-carbamic acid tert-butyl ester as a light yellow oil (2.4 g, 74% yield, dr=62:38) [dr=62:38 was determined by integration of one set of 1H NMR signal (major s, 9.68 ppm, minor s, 9.76 ppm)]. 1HNMR (400 MHz, CDCl3) 9.76 (s, 1H), 9.68 (s, 1H), 7.34 (d, J=1.57 Hz, 1H), 6.38-6.17 (m, 2H), 5.08 (m, 2H), 2.94 (m, 1H), 1.44 (s, 9H), 1.09 (t, 3H).

1. customthe reaction mixture was quenched with water (20 mL)
2. extractionextracted with EtOAc (3×30 mL)
3. dry with materialThe organic layer was dried over Na2SO4
4. filtrationfiltered
5. concentrationconcentrated in vacuo
6. customThe crude residue was purified by column chromatography on silica gel (EtOAc/heptane)