反应详情

Tetrahedron, 57 (2001), 5183. A mixture of Montmorillonite K10 (188 g, 571 mmol) in trimethyl orthoformate (316 mL, 2856 mmol) was stirred for 2 hrs under nitrogen. To the mixture was slowly added methyl 2-(3-oxocyclopentyl)acetate (89.2 g, 571 mmol), as a suspension in pentane (500 mL). The mixture was stirred for 16 hrs, then filtered through a CELITE® pad rinsing with pentane. The filtrate was concentrated under reduced pressure to afford the title compound (104.9 g, 519 mmol, 91% yield) as an amber oil. 1H NMR (400 MHz, CDCl3) δ ppm 3.67 (3 H, s) 3.20 (6 H, s) 2.35-2.46 (3 H, m) 2.11 (1 H, dd, J=13.18, 7.40 Hz) 1.86-1.96 (2 H, m) 1.74-1.83 (1 H, m) 1.44 (1 H, dd, J=13.05, 8.53 Hz) 1.34 (1 H, dd, J=12.55, 8.78 Hz). 13C NMR (101 MHz, CDCl3) δ ppm 172.73, 110.91, 50.93, 48.80, 48.61, 40.27, 39.66, 33.51, 33.25, 29.37.

1. stirringThe mixture was stirred for 16 hrs
2. filtrationfiltered through a CELITE® pad
3. washrinsing with pentane
4. concentrationThe filtrate was concentrated under reduced pressure