反应详情

Methoxymethyl triphenylphosphonium chloride (2.74 g, 8 mmol, 2.0 equiv.) and potassium tert-butoxide (1.35 g, 12 mmol, 3.0 equiv.) were weighed into a 250-mL oven-dried flask. Tetrahydrofuran (15 mL) was slowly introduced via syringe under nitrogen. After the resulting red solution was stirred at room temperature for 10 min, 7-methylindazole aldehyde (641 mg, 1.0 equiv.) was added in one portion. LCMS indicated that the reaction was complete within 1 h. The reaction was quenched with water and the mixture was then diluted with ethyl acetate. The layers were separated and the organic layer was washed with brine, dried over sodium sulfate and concentrated in vacuo to give a tan oil. The crude product was purified by flash column chromatography on silica gel (1:1 hexane/ethyl acetate) to afford the desired product as an off-white solid (710 mg, 94%). MS (ESI) [M+H]+=189; 1H NMR indicated a mixture of isomers (trans/cis ˜3:1). Trans isomer: 1H-NMR (400 MHz, CDCl3) δ 12.3 (br., 1H), 8.13 (s, 1H), 7.88 (s, 1H), 7.42 (s, 1H), 6.12 (d, J=7.0 Hz, 1H), 5.31 (d, J=7.0 Hz, 1H), 3.80 (s, 3H), 2.60 (s, 3H).

1. customoven-dried flask
2. additionTetrahydrofuran (15 mL) was slowly introduced via syringe under nitrogen
3. waitwas complete within 1 h
4. customThe reaction was quenched with water
5. additionthe mixture was then diluted with ethyl acetate
6. customThe layers were separated
7. washthe organic layer was washed with brine
8. dry with materialdried over sodium sulfate
9. concentrationconcentrated in vacuo
10. customto give a tan oil
11. customThe crude product was purified by flash column chromatography on silica gel (1:1 hexane/ethyl acetate)