Triphenylphosphine → 6-bromo-2,2-dimethyl-4H-spiro[chromene-3,3'-oxetan]-4-one

HRID 594863

Reaction equation

HRID 594863 reaction equation
[Br:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[C:6]([CH2:16][OH:17])([CH2:14]O)[C:5]2=[O:18].C1(P(C2C=CC=CC=2)C2C=CC=CC=2)C=CC=CC=1.N(C(OC(C)C)=O)=NC(OC(C)C)=O>C1COCC1.C1(C)C=CC=CC=1.CN(C)C(=S)[S-].CN(C)C(=S)[S-].[Zn+2]>[Br:1][C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[C:6]1([CH2:16][O:17][CH2:14]1)[C:5]2=[O:18]

Participants

7

Reactant 3

HCID 11776TriphenylphosphineHCID 75555Diisopropyl diazene-1,2-dicarboxylateHCID 867242446-bromo-3,3-bis(hydroxymethyl)-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one

Product 1

HCID 867242436-bromo-2,2-dimethyl-4H-spiro[chromene-3,3'-oxetan]-4-oneYield 34.9%

Reagents, catalysts & solvents 3

HCID 8722ZiramCatalystHCID 1140TolueneSolventHCID 8028TetrahydrofuranSolvent

Procedure

To a mixture of 6-bromo-3,3-bis(hydroxymethyl)-2,2-dimethyl-2,3-dihydro-4H-chromen-4-one (6.76 g, 21.4 mmol), zinc bis(dimethyldithiocarbamate) (26.2 g, 85.8 mmol) and triphenylphosphine (8.44 g, 32.2 mmol) in THF (0.20 L) was added diisopropyl azodicarboxylate (1.9 M solution in toluene, 16.9 mL, 32.2 mmol) in an ice-water bath. The mixture was stirred overnight at ambient temperature. The mixture was diluted with toluene (0.20 L), and the mixture was filtered off. The filtrate was washed with 1 M aqueous NaOH (three times), water and brine, dried over MgSO4 and filtered. The filtrate was evaporated to give a crude product. The crude product was purified with column chromatography on silica gel (Hexane-EtOAc, a linear gradient of EtOAc from 0 to 20%) to afford 6-bromo-2,2-dimethyl-4H-spiro[chromene-3,3′-oxetan]-4-one (2.22 g).

Workup

  1. filtrationthe mixture was filtered off
  2. washThe filtrate was washed with 1 M aqueous NaOH (three times), water and brine
  3. dry with materialdried over MgSO4
  4. filtrationfiltered
  5. customThe filtrate was evaporated
  6. customto give a crude product
  7. customThe crude product was purified with column chromatography on silica gel (Hexane-EtOAc

Sources & evidence

ORD record
ord-6c66971247fc4a2391c9870c1af9bea4
Source dataset
uspto-grants-2016_01
Patent number
US09242973B2

Linked notes

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