Benzofuran → 2-Vinyl-7-benzyloxy-6-methoxydihydrobenzofuran

HRID 1684061Notes

Reaction equation

HRID 1684061 reaction equation
O1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:4]=2C=C1.OCCS(C1C=C([C@H]2S[C@H](C3C=C(OC)C(OC)=C(OC)C=3)CS2)C=C(OC)C=1OCCC)(=O)=O.[CH2:45]([Li])[CH2:46][CH2:47][CH3:48].OC1C([N+]([O-])=O)=CC([C@H]2S[C@H]([C:65]3[CH:70]=[C:69]([O:71]C)[C:68]([O:73][CH3:74])=[C:67]([O:75][CH3:76])[CH:66]=3)CS2)=CC=1OC.COC1C=C([C@H]2S[C@H](C3C=C(OC)C(OC)=C(OC)C=3)CS2)C=C([N+]([O-])=O)C=1OC>C1(C)C=CC=CC=1.C(OCC)(=O)C>[CH:47]([CH:46]1[CH2:45][C:70]2[CH:65]=[CH:66][C:67]([O:75][CH3:76])=[C:68]([O:73][CH2:74][C:4]3[CH:9]=[CH:8][CH:7]=[CH:6][CH:5]=3)[C:69]=2[O:71]1)=[CH2:48]

Participants

8

Reactant 5

HCID 9223BenzofuranHCID 86749583trans-2-(4-Hydroxy-3-methoxy-5-nitrophenyl)-4-(3,4,5-trimethoxyphenyl)-1,3-dithiolaneHCID 86750974trans-2-(3,4-Dimethoxy-5-nitrophenyl)-4-(3,4,5-trimethoxyphenyl)-1,3-dithiolaneHCID 86750981trans-2-(3-(2-Hydroxyethylsufonyl)-5-methoxy-4-propoxyphenyl)-4-(3,4,5-trimethoxyphenyl)-1,3-dithiolaneHCID 178418339Butyllithium2×

Product 1

HCID 190417952-Vinyl-7-benzyloxy-6-methoxydihydrobenzofuran

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Procedure

Using the procedure of Bigi et al, Tetrahedron, 39, 169 (1983), the benzofuran system is constructed. N-butyl lithium (3.95 ml of a 2.2M solution) is added to a solution of 3-benzyloxy-4-methoxyphenol (203, prepared as described in Example 32)(2.0 g, 0.0087 mols) in dry toluene. Upon addition of the n-butyl lithium, a precipitate falls out of solution. After all the n-butyl lithium is added, the reaction is starred for 15-20 minutes at room temperature. Subsequently, the reaction is heated to reflux for twenty one hours. The reaction is then diluted with ethyl acetate and washed with 10% HCl and water. The extract is dried over sodium sulfate. The crude reaction mixture is purified by flash column chromotography using 2:1 hexane-ethyl acetate as eluant to obtain two major products which are (1) unreacted starting material and (2) product (0.979 g, 37.6%)

Workup

  1. temperatureSubsequently, the reaction is heated
  2. temperatureto reflux for twenty one hours
  3. washwashed with 10% HCl and water
  4. dry with materialThe extract is dried over sodium sulfate
  5. customThe crude reaction mixture
  6. customis purified by flash column chromotography
  7. customto obtain two major products which

Sources & evidence

ORD record
ord-3b339500be414512aaae5a6024c2c588
Source dataset
uspto-grants-1997_06
Patent number
US05639782

Reaction notes

Loading…