6-fluoro-4-oxo-4H-chromene-2-carboxylic acid → 6-fluoro-4-oxo-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid

HRID 1681437Notes

Reaction equation

HRID 1681437 reaction equation
[F:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][C:9]([C:11]([OH:13])=[O:12])=[CH:8][C:7](=[O:14])[C:6]=2[CH:15]=1>C1C=CC=CC=1.[Rh].CO>[F:1][C:2]1[CH:3]=[CH:4][C:5]2[O:10][CH:9]([C:11]([OH:13])=[O:12])[CH2:8][C:7](=[O:14])[C:6]=2[CH:15]=1

Participants

5

Reactant 1

HCID 40960466-fluoro-4-oxo-4H-chromene-2-carboxylic acid

Product 1

HCID 27785256-fluoro-4-oxo-3,4-dihydro-2H-1-benzopyran-2-carboxylic acid

Reagents, catalysts & solvents 3

HCID 23948RhodiumCatalystHCID 241BenzeneSolvent2×HCID 887MethanolSolvent

Procedure

(+)-2,3-O-isopropyliden-2,3-dihydroxy-1,4-bis(diphenylphosphyno)butane (120 mg, 0.0240 mmol) was added to a solution of dichloro-bis-[(1,3)-cyclooctadiene]-dirhodium(I) (59.2 mg, 0.0120 mmol) in dry benzene (0.5 ml) under argon atomosphere and the mixture was stirred for 15 minutes to prepare an optical active rhodium catalyst. The benzene solution (catalyst) was added to a suspension of 6-fluoro-4-oxo-4H-1-benzopyran-2-carboxylic acid (1.00 g, 4.80 mmol, obtained in Example 5) in methanol (30 ml) under argon atmosphere. Gaseous phase was changed for H2, and the mixture was stirred for 24 hours under H2 (4 kg/cm2) at 40° C.

Workup

  1. stirringthe mixture was stirred for 24 hours under H2 (4 kg/cm2) at 40° C.

Sources & evidence

ORD record
ord-43194e4f1f434b77bcf386f3fcfcedee
Source dataset
uspto-grants-1992_12
Patent number
US05171865

Reaction notes

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