Imidazole → Ethyl 5(r)-t-butyldimethylsilyloxyhexanoate

反応式

[OH:1][C@H:2]([CH3:11])[CH2:3][CH2:4][CH2:5][C:6]([O:8][CH2:9][CH3:10])=[O:7].N1C=CN=C1.[Si:17](Cl)([C:20]([CH3:23])([CH3:22])[CH3:21])([CH3:19])[CH3:18]>CN(C=O)C>[Si:17]([O:1][C@H:2]([CH3:11])[CH2:3][CH2:4][CH2:5][C:6]([O:8][CH2:9][CH3:10])=[O:7])([C:20]([CH3:23])([CH3:22])[CH3:21])([CH3:19])[CH3:18]

参加物

実験手順

A solution of ethyl 5(R)-hydroxyhexanoate 3 (1.80 g, 11.24 mmol), imidazole (2.3 g, 33.8 mmol), and t-butyldimethylsilyl chloride (2.54 g, 16.85 mmol) in 30 mL of DMF was stirred at 23° C. overnight (19 h). The solvent (DMF) was then removed in vacuo and aqueous saturated sodium bicarbonate (100 mL) was added followed by ethyl acetate (100 mL). The layers were separated and the aqueous layer was re-extracted with 100 mL of EtOAc. The combined organic layers were washed with water, brine, and dried over anhydrous sodium sulfate. Flash column chromatographic purification on 30 g of silica gel yielded 2.71 g (88%) of TBDMS-ether 4 (G.C. purity of 99+A %); 1H NMR (CDCl3): 0.04 (s, 6H), 0.91 (s, 9H), 1.18 (d, J=6 Hz, 3H), 1.25 (t, J=7.2 Hz, 3H), 1.42 (m, 2H), 1.65 (m, 2H), 2.39 (t, J=7.5 Hz, 2H), 3.79 (m, J=6 Hz, 1H), 4.12 (q, J=7.2 Hz, 2H).