反应详情

Compound 2j (320 mg, 1.38 mmol) and p-TSA (40 mg) are dissolved in dry acetone (2 ml) and 2,2-dimethoxypropane (2 ml). The resulting solution is heated overnight at reflux. Solid K2CO3 is added and the volatiles removed in vacuo to give a residue. Flash chromatography (2×21 cm column, 6:1 hexane/EtOAc) of the residue provides 8a as an oil: NMR δ 0.88 (m, 3H), 1.29 (m, 6H), 1.57 (s, 3H), 1.62 (m, 2H), 1.70 (s, 3H), 2.15 (m, 2H), 3.81 (s, 3H), 4.20 (m, 2H), 4.46 (m, 1H); [α]D26 =-47±1 (CHCl3).

1. temperatureThe resulting solution is heated overnight
2. temperatureat reflux
3. customthe volatiles removed in vacuo
4. customto give a residue