反应详情

In a round bottomed flask, at −78° C., under argon atmosphere, a solution of DIPA (0.3 mL, 2.12 mmol) in dry THF (10 ml) was treated with n-BuLi (2.5 M in n-hexane, 0.776 mL, 1.94 mmol). After 30 min a solution of ethyl 2-(dibenzylamino)-acetate (0.5 g, 1.77 mmol) in dry THF (10 ml) was added dropwise via a cannula. After 15 min, propanoyl chloride (0.46 mL, 5.29 mmol) was added dropwise at −78° C. and the mixture stirred for 10 min at rt. The reaction was then quenched with H2O, and Et2O was subsequently added. The organic layer was washed with brine, dried over Na2SO4, filtered, and concentrated in vacuo to give a crude product, as an oil. Purification by column chromatography using a Teledyne ISCO apparatus, eluting with Cy:AcOEt (98:2) gave a pure compound (0.6 g), as a mixture of two tautomers (ketone:enol=ca. 85:15), as a colorless oil. MS (ESI) m/z: 340 [M−H]+; (ESI) m/z: 338 [M−H]−. 1H NMR (DMSO-d6) δ 0.90 (t, J=7.24 Hz, 3H), 1.23 (t, J=7.07 Hz, 3H), 2.53-2.61 (m, 1H), 2.69 (dq, J=7.23, 18.13 Hz, 1H), 3.72-3.88 (m, 4H), 4.12-4.22 (m, 3H), 7.11-7.47 (m, 10H) (reported data refer to the major ketone tautomer).

1. customThe reaction was then quenched with H2O, and Et2O
2. additionwas subsequently added
3. washThe organic layer was washed with brine
4. dry with materialdried over Na2SO4
5. filtrationfiltered
6. concentrationconcentrated in vacuo
7. customto give a crude product
8. customPurification by column chromatography
9. washeluting with Cy