反应详情

To a solution of ethyl 1,4-dioxaspiro[4.5]decane-8-carboxylate (15 g, 70.0 mmol, 1 equiv) in THF (200 mL) at 0° C. (ice water bath), was added LiHMDS (98 mL of a 1 M solution in THF, 98 mmol, 1.4 equiv) in 4 portions over ˜2 min. After stirring 1 h, N-fluoro-di(benzenesulfonyl)-amine (26.5 g, 84 mmol, 1.2 equiv) was added. The reaction was stirred 20 min then poured into a saturated aqueous solution of NaHCO3. The aqueous solution was extracted with ether (×3). The combined ether layers were dried (MgSO4) and concentrated in vacuo. Crude residue was stirred with hexane (˜600 mL) and filtered. The filtrate was concentrated in vacuo to give 16.68 g of the crude product as a yellow oil. ˜4:1 product:sm. Taken on as is to the ester reduction. 1H NMR (400 MHz, CDCl3) δ ppm 4.25 (q, J=7.11 Hz, 2H), 3.94-4.00 (m, 4H), 2.02-2.26 (m, 4H), 1.92 (td, J=13.30, 4.77 Hz, 2H), 1.66-1.77 (m, 2H), 1.31 (t, J=7.03 Hz, 3H); 19F NMR (376 MHz, CDCl3) δ ppm −168.50 (br. s., 1F).

1. stirringThe reaction was stirred 20 min
2. extractionThe aqueous solution was extracted with ether (×3)
3. dry with materialThe combined ether layers were dried (MgSO4)
4. concentrationconcentrated in vacuo
5. stirringCrude residue was stirred with hexane (˜600 mL)
6. filtrationfiltered
7. concentrationThe filtrate was concentrated in vacuo