反应详情

A mixture of Wieland-Miescher ketone (5.086 g, 28.44 mmol), 2-methyl-2-ethyl-1,3-dioxolane (19.38 mL, 155.0 mmol), ethylene glycol (0.358 mL, 6.43 mmol) and p-toluenesulfonic acid monohydrate (0.4 g, 2.13 mmol) was stirred at room temperature for 30 hours. The reaction was quenched with dropwise addition of triethylamine, diluted with 20 mL of benzene, washed with water, dried over MgSO4and concentrated under vacuum. The product was triturated from hexanes to yield monoacetal 201 (5.92 g, 94%). 1H NMR (CDCl3) δ 1.36 (s, 3H), 1.6-2.0 (m, 5H), 2.2-2.5 (m, 5H), 3.9-4.1 (m, 4H), 5.80 (d, J=Hz, 1H); 13C NMR (CDCl3) 198.91, 167.55, 125.38, 125.37, 112.12, 65.16, 64.84, 44.81, 33.70, 31.22, 29.81, 26.62, 21.51, 20.27.

1. customThe reaction was quenched with dropwise addition of triethylamine
2. additiondiluted with 20 mL of benzene
3. washwashed with water
4. customdried over MgSO4and
5. concentrationconcentrated under vacuum
6. customThe product was triturated from hexanes