Ethylene Glycol → 2-(1,3-Dioxolan-2-yl)-3-bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene

HRID 1836887Notes

Reaction equation

HRID 1836887 reaction equation
[CH:1]([C:3]1[C:12]([Br:13])=[CH:11][C:10]2[C:9]([CH3:15])([CH3:14])[CH2:8][CH2:7][C:6]([CH3:17])([CH3:16])[C:5]=2[CH:4]=1)=[O:2].[CH2:18](O)[CH2:19][OH:20].O.C1(C)C=CC(S(O)(=O)=O)=CC=1>C1C=CC=CC=1>[O:2]1[CH2:18][CH2:19][O:20][CH:1]1[C:3]1[C:12]([Br:13])=[CH:11][C:10]2[C:9]([CH3:15])([CH3:14])[CH2:8][CH2:7][C:6]([CH3:17])([CH3:16])[C:5]=2[CH:4]=1

Participants

5

Reactant 3

HCID 174Ethylene GlycolHCID 521998p-Toluenesulfonic acid monohydrateHCID 177898873-Bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene-2-carbaldehyde

Product 1

HCID 234989352-(1,3-Dioxolan-2-yl)-3-bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthaleneYield 72%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

To a solution of 1.8 g (6.3 mmol) of 2-formyl-3-bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene in 70 mL of benzene was added 3.5 mL of ethylene glycol (63 mmol) followed by p-toluenesulfonic acid monohydrate (180 mg, 0.9 mmol). The reaction mixture was heated at reflux for about 3 hours and is then concentrated under reduced pressure. The residue was partitioned between ether and saturated sodium bicarbonate solution. The ether layer was washed with brine, dried over MgSO4 and concentrated under reduced pressure. The residue was purified by flash chromatography 1.4% ethyl acetate/) on a Biotage 40M SiO2 cartridge to afford 1.5 g (72%) of 2-(1,3-dioxolan-2-yl)-3-bromo-5,5,8,8-tetramethyl-5,6,7,8-tetrahydronaphthalene as a crystalline solid.

Workup

  1. temperatureThe reaction mixture was heated
  2. temperatureat reflux for about 3 hours
  3. concentrationis then concentrated under reduced pressure
  4. customThe residue was partitioned between ether and saturated sodium bicarbonate solution
  5. washThe ether layer was washed with brine
  6. dry with materialdried over MgSO4
  7. concentrationconcentrated under reduced pressure
  8. customThe residue was purified by flash chromatography 1.4% ethyl acetate/) on a Biotage 40M SiO2 cartridge

Sources & evidence

ORD record
ord-7a2a360e899447d4969c686a5191a018
Source dataset
uspto-grants-2004_08
Patent number
US06777418B2

Reaction notes

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