反应详情

To a mixture of 3,4-bis-methoxymethoxy-benzaldehyde (100 mmol) and (4-methoxycarbonyl-benzyl)-triphenyl-phosphonium bromide (100 mmol) in of EtOH (300 mL) at 0° C. was added slowly of a lithium ethoxide solution (101 mL, 1 M in EtOH). Upon the completion of the addition, the cold bath was removed and the reaction was allowed to warm to room temperature. The stirring was continued for additional 2 h. The solvent was then removed by rotary evaporation and residue was taken up to 500 mL of EtOAc and washed with ammonium chloride solution (2×100 mL) and water. The organic layer was dried over Na2SO4 and the crude product was purified on silica (hexane:EtOAc=2:1) to afford a clear sticky solid (yield 99%). NMR indicated the purified product is a mixture of cis/trans isomers containing ethyl and methyl esters. 1H-NMR (300 MHz, CDCl3) δ 8.02 (d, J=0.84, 1.5H), 7.93 (d, J=0.84, 0.5H), 7.91 (s, 0.3H), 7.55 (s, 0.75H), 7.52 (s, 0.75H), 7.38-7.33 (m, 1.25H), 7.17-7.12 (m, 2.25H), 7.03-6.98 (m, 1.25H), 6.84 (m, 0.25H), 6.61-6.52 (m, 0.5H), 5.29-5.05 (m, 4H), 4.41-4.25 (m, 1H), 3.90 (s, 1.5H), 3.56-3.39 (m, 6H), 1.40 (q, J=6 Hz, 1.5H).

1. additionUpon the completion of the addition
2. customthe cold bath was removed
3. customThe solvent was then removed by rotary evaporation and residue
4. washwashed with ammonium chloride solution (2×100 mL) and water
5. dry with materialThe organic layer was dried over Na2SO4
6. customthe crude product was purified on silica (hexane:EtOAc=2:1)