反应详情

To a solution of keto aldehyde 19 (6.40 g, 50 mmol) in isopropanol (100 mL) was added triisopropyl orthoformate (16.7 mL, 75 mmol) and p-TsOH (951 mg, 5.0 mmol). After the mixture was stirred for 3 h, it was poured into brine (100 mL) and extracted with ether (3×100 mL). The combined organic layers were dried and concentrated in vacuo to give 50 as a pale yellow liquid (10.12 g, 88%: IR (neat) 2976, 2935, 1697, 1460, 1379, 1314, 1174, 1125, 1082, 1028 cm−1; 1H NMR (300 MHz, CDCl3) δ 4.58 (s, 1H), 3.80 (sept, J=6.1 Hz, 2H), 2.51 (q, J=7.2 Hz, 2H), 1.18 (d, J=6.2 Hz, 6H), 1.12 (s, 6H), 1.08 (d, J=6.2 Hz, 6H), 0.95 (t, J=7.2 Hz, 3H); 13C NMR (75 MHz, CDCl3) δ 215.8, 104.0, 70.7, 53.4, 32.8, 23.8, 22.4, 20.3, 8.0; HRMS calcd for C10H19O2 (M-C3H7) 171.1385, found 171.1377.

1. extractionextracted with ether (3×100 mL)
2. customThe combined organic layers were dried
3. concentrationconcentrated in vacuo