Formic Acid → HCID 68447935, compound

Reaction equation

[CH2:1]([O:3][C:4]1[CH:20]=[CH:19][C:7]2[CH:8]3[CH2:18][CH2:17][C:12]4(OCC[O:13]4)[CH2:11][CH:9]3[O:10][C:6]=2[C:5]=1[F:21])[CH3:2].C(O)=O.O>C1(C)C=CC=CC=1>[CH2:1]([O:3][C:4]1[CH:20]=[CH:19][C:7]2[CH:8]3[CH2:18][CH2:17][C:12](=[O:13])[CH2:11][CH:9]3[O:10][C:6]=2[C:5]=1[F:21])[CH3:2]

Participants

Procedure

135.0 g (459 mmol) of (±)-(4aR*, 9bS*)-7-ethoxy-6-fluoro-1,4,4a,9b-tetrahydro-2H-spiro[dibenzo[b,d]furan-3,2′-1,3-dioxolane] are dissolved in 1800 ml of toluene and stirred vigorously together with 550 ml (14.6 mol) of formic acid with addition of 10.0 ml (0.56 mol) of water. After 18 h, the organic phase is separated off, and the formic acid is extracted with toluene. The combined organic phases are washed successively with water, sat. sodium hydrogencarbonate solution and sat. sodium chloride solution and dried using sodium sulfate. The crude product remaining after removal of the solvent is purified by column chromatography (SiO2, toluene:ethyl acetate=4:1), giving (±)-(4aR*, 9bS*)-7-ethoxy-6-fluoro-1,4,4a,9b-tetrahydro-2H-dibenzofuran-3-one as colourless solid.