Acetic Anhydride → trans-2-[3-(2-Oxopropylsulfonyl)-4-n-propoxy-5-benzyloxyphenyl]-5-(3,4,5-trimethoxyphenyl)tetrahydrofuran

HRID 982468Notes

Reaction equation

HRID 982468 reaction equation
[CH3:1][S:2]([C:5]1[CH:6]=[C:7]([C@H:23]2[CH2:27][CH2:26][C@H:25]([C:28]3[CH:33]=[C:32]([O:34][CH3:35])[C:31]([O:36][CH3:37])=[C:30]([O:38][CH3:39])[CH:29]=3)[O:24]2)[CH:8]=[C:9]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C:10]=1[O:11][CH2:12][CH2:13][CH3:14])(=[O:4])=[O:3].[Li]CCCC.[C:45](OC(=O)C)(=[O:47])[CH3:46].[Cl-].[NH4+]>C1COCC1.CCOCC.O>[O:47]=[C:45]([CH3:46])[CH2:1][S:2]([C:5]1[CH:6]=[C:7]([C@H:23]2[CH2:27][CH2:26][C@H:25]([C:28]3[CH:33]=[C:32]([O:34][CH3:35])[C:31]([O:36][CH3:37])=[C:30]([O:38][CH3:39])[CH:29]=3)[O:24]2)[CH:8]=[C:9]([O:15][CH2:16][C:17]2[CH:22]=[CH:21][CH:20]=[CH:19][CH:18]=2)[C:10]=1[O:11][CH2:12][CH2:13][CH3:14])(=[O:4])=[O:3]

Participants

8

Reactant 4

HCID 7918Acetic AnhydrideHCID 25517Ammonium ChlorideHCID 15078288racemic trans-2-(3-Methylsulfonyl-4-n-propoxy-5-benzyloxyphenyl)-5-(3,4,5-trimethoxyphenyl) tetrahydrofuranHCID 178418339Butyllithium

Product 1

HCID 15078289trans-2-[3-(2-Oxopropylsulfonyl)-4-n-propoxy-5-benzyloxyphenyl]-5-(3,4,5-trimethoxyphenyl)tetrahydrofuran

Reagents, catalysts & solvents 3

HCID 962WaterSolventHCID 3283Diethyl EtherSolventHCID 8028TetrahydrofuranSolvent

Procedure

2.7 g trans-2-(3-methylsulfonyl-4-n-propoxy-5-benzyloxyphenyl)-5-(3,4,5-trimethoxyphenyl)tetrahydrofuran (STEP I) dissolved in 15 mL THF was cooled to -78° and treated with 5.3 mL of 1.6M n-BuLi. After about 5 minutes of stirring, to the resulting dark solution, 1.0 mL of acetic anhydride was added. The yellow reaction mixture was allowed to warm up to room temperature and treated with 3-4 g of solid ammonium chloride, water and ether. NMR showed that the desired ketosulfone has formed to the extent of 80%. The ether layer was separated, dried over NaSO4, evaporated and chromatographed over silica (20% ethyl acetate in hexane) to yield the title compound after crystallization from ether: NMR(200 MHz, CDCl3) δ 0.98(t, CH2CH2CH3), 1.83(m, CH2CH2CH3), 1.9-2.6(m, 3-CH2 and 4-CH2), 2.38(s, CH3C(O)CH2), 3.86(s, OCH3), 3.88(s, 2 OCH3), 4.18(t, OCH2CH2CH3), 4.48(s, CH3C(O)CH2), 5.18(s, OCH2Ar), 5.06-5.28(m, 2-CH and 5-CH), 6.61(s, 5-ArH), 7.32-7.54(m, ArH).

Workup

  1. temperaturewas cooled to -78°
  2. additionwas added
  3. customhas formed to the extent of 80%
  4. customThe ether layer was separated
  5. dry with materialdried over NaSO4
  6. customevaporated
  7. customchromatographed over silica (20% ethyl acetate in hexane)

Sources & evidence

ORD record
ord-62e1a5bea2f74488b6e330a939e0a935
Source dataset
uspto-grants-1991_02
Patent number
US04996203

Reaction notes

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