反应详情

To a solution of ethyl 4-(tert-butyldimethylsilyloxy)-2-ethylcyclopentanecarboxylate (0.200 g, 0.666 mmol, Example #22 Step D) in MeCN (4.5 mL) was added triethylsilane (0.160 mL, 1.00 mmol) and bismuth(III) bromide (0.020 g, 0.045 mmol). The reaction mixture was stirred at ambient temperature for about 1 min followed by dropwise addition of dihydro-2H-pyran-4(3H)-one (0.100 g, 0.998 mmol). The reaction mixture was stirred at ambient temperature for about 15 min. The reaction was filtered through an Acrodisc® and the solvent was removed under reduced pressure. The crude material was purified by silica gel chromatography using a gradient of 10-100% EtOAc in heptane to give ethyl 2-ethyl-4-(tetrahydro-2H-pyran-4-yloxy)cyclopentanecarboxylate (0.253 g, 94%) as a colorless oil; 1H NMR (400 MHz, CDCl3) δ 4.13 (q, J=7.1, 2H), 4.05-3.98 (m, 1H), 3.98-3.88 (m, 2H), 3.58-3.47 (m, 1H), 3.46-3.36 (m, 2H), 2.80 (q, J=8.5, 1H), 2.16 (dt, J=13.3, 7.7, 1H), 2.09-1.93 (m, 3H), 1.90-1.81 (m, 2H), 1.62-1.49 (m, 3H), 1.43 (ddd, J=11.1, 7.4, 5.2, 1H), 1.33-1.22 (m, 4H), 0.92-0.83 (m, 3H).

1. stirringThe reaction mixture was stirred at ambient temperature for about 15 min
2. filtrationThe reaction was filtered through an Acrodisc®
3. customthe solvent was removed under reduced pressure
4. customThe crude material was purified by silica gel chromatography