Formaldehyde → Isochromane

HRID 432939

Reaction equation

HRID 432939 reaction equation
[CH2:1]([OH:9])[CH2:2][C:3]1[CH:8]=[CH:7][CH:6]=[CH:5][CH:4]=1.[CH2:10]=O>C(O)(=O)C.C(Cl)Cl>[CH2:10]1[C:8]2[C:3](=[CH:4][CH:5]=[CH:6][CH:7]=2)[CH2:2][CH2:1][O:9]1

Participants

5

Reactant 2

HCID 712FormaldehydeHCID 60542-Phenylethanol

Product 1

HCID 96266IsochromaneYield 40.2%

Reagents, catalysts & solvents 2

HCID 176Acetic AcidSolventHCID 6344DichloromethaneSolvent

Procedure

To a solution of phenethyl alcohol (122 mg, 1.0 mmol) in glacial acetic acid (2 mL) was added formaldehyde (40% in water, 100 μl, 1.5 mmol) and Yb(CNf3)3 (276 mg, 0.1 mmol, 10 mol %). The mixture was stirred at reflux for 18 hours. The mixture was allowed to cool, diluted with CH2Cl2, washed with water, aqueous sodium hydrogen carbonate solution, and brine, dried over MgSO4, filtered and evaporated. Chromatography (3:1 PE:Et2O) gave isochroman (54 mg, 40%) as a colourless oil: IR (thin film; NaCl plate) 2929, 2851, 1605, 1585 cm−1; δH (300 MHz, CDCl3) 7.23-7.14 (3H, m, Ar—H×3), 7.04-7.00 (1H, m, Ar—H), 4.82 (2H, s, ArCH2O), 4.04 (2H, t, J=5.7 Hz, ArCH2OCH2), 2.90 (2H, t, J=5.7 Hz, ArCH2CH2); δC (75 MHz, CDCl3) 135.0, 133.3, 129.0, 126.4, 126.0, 124.4, 68.0, 65.4, 28.4; MS 134 (M+), 104, 77, 51.

Workup

  1. temperatureat reflux for 18 hours
  2. temperatureto cool
  3. washwashed with water, aqueous sodium hydrogen carbonate solution, and brine
  4. dry with materialdried over MgSO4
  5. filtrationfiltered
  6. customevaporated

Sources & evidence

ORD record
ord-ea6d30e65e78480b9795e5e78a3f3f98
Source dataset
uspto-grants-2003_12
Patent number
US06664380B1

Linked notes

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