Ethylene Glycol → 2-Benzyl-2-(4-bromophenyl)-1,3-dioxolane

HRID 1678798Notes

Reaction equation

HRID 1678798 reaction equation
[Br:1][C:2]1[CH:7]=[CH:6][C:5]([C:8](=[O:16])[CH2:9][C:10]2[CH:15]=[CH:14][CH:13]=[CH:12][CH:11]=2)=[CH:4][CH:3]=1.[CH2:17](O)[CH2:18][OH:19].CC1C=CC(S(O)(=O)=O)=CC=1>C1(C)C=CC=CC=1.C(OCC)(=O)C>[CH2:9]([C:8]1([C:5]2[CH:4]=[CH:3][C:2]([Br:1])=[CH:7][CH:6]=2)[O:19][CH2:18][CH2:17][O:16]1)[C:10]1[CH:11]=[CH:12][CH:13]=[CH:14][CH:15]=1

Participants

6

Reactant 3

HCID 174Ethylene GlycolHCID 6101p-Toluenesulfonic acidHCID 5197381-(4-Bromophenyl)-2-phenylethanone

Product 1

HCID 142569482-Benzyl-2-(4-bromophenyl)-1,3-dioxolane

Reagents, catalysts & solvents 2

HCID 1140TolueneSolventHCID 8857Ethyl AcetateSolvent

Procedure

A solution of 1-(4-bromophenyl)-2-phenylethanone (5.0 g, 18 mmol), ethylene glycol (3.0 mL, 54 mmol) and tosic acid (0.04 g, 0.2 mmol) in toluene (30 mL) was heated to reflux with a Dean-Stark trap for 15 hours. The reaction was cooled to room temperature, diluted with ethyl acetate, washed with saturated sodium bicarbonate, brine, dried over sodium sulfate, filtered and concentrated to give crude 2-benzyl-2-(4-bromophenyl)-1,3-dioxolane as a white solid. To the crude material was added zinc cyanide (2.3 g, 20 mmol), tetrakis(triphenylphosphine)palladium (3.3 g, 2.8 mmol), DMF (20 mL) and dioxane (20 mL) and the resulting suspension was purged with nitrogen for 15 minutes prior to being heated 100° C. for 15 hours. The reaction was cooled to room temperature, poured into ether and filtered. The organic filtrate was washed with water, saturated bicarbonate, brine, dried over sodium sulfate, filtered and concentrated. Purification by silica gel chromatography (1% ethyl acetate/hexane→50% ethyl acetate/hexane) gave the title compound as white solid. MS (M+H+): calculated=265.31, observed=266.1.

Workup

  1. temperatureto reflux with a Dean-Stark trap for 15 hours
  2. washwashed with saturated sodium bicarbonate, brine
  3. dry with materialdried over sodium sulfate
  4. filtrationfiltered
  5. concentrationconcentrated

Sources & evidence

ORD record
ord-571104d3ceca4ed98792966081fff34d
Source dataset
uspto-grants-2011_08
Patent number
US08008317B2

Reaction notes

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