Tris(1,1-dimethylethyl)phosphine → Methyl 6-(2,6-difluoro-4-methoxyphenyl)-5-fluoropicolinate

HRID 705183Notes

Reaction equation

HRID 705183 reaction equation
Br[C:2]1[N:7]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[CH:5]=[CH:4][C:3]=1[F:12].[F:13][C:14]1[CH:19]=[C:18]([O:20][CH3:21])[CH:17]=[C:16]([F:22])[C:15]=1B(O)O.[F-].[K+].C(P(C(C)(C)C)C(C)(C)C)(C)(C)C>C1COCC1.O.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.C1C=CC(/C=C/C(/C=C/C2C=CC=CC=2)=O)=CC=1.[Pd].[Pd]>[F:13][C:14]1[CH:19]=[C:18]([O:20][CH3:21])[CH:17]=[C:16]([F:22])[C:15]=1[C:2]1[N:7]=[C:6]([C:8]([O:10][CH3:11])=[O:9])[CH:5]=[CH:4][C:3]=1[F:12]

Participants

8

Reactant 4

HCID 83681Tris(1,1-dimethylethyl)phosphineHCID 522689Potassium FluorideHCID 162174242,6-Difluoro-4-methoxybenzeneboronic acidHCID 46311204Methyl 6-bromo-5-fluoropyridine-2-carboxylate

Product 1

HCID 59226460Methyl 6-(2,6-difluoro-4-methoxyphenyl)-5-fluoropicolinateYield 85%

Reagents, catalysts & solvents 3

HCID 9811564Bis(dibenzylideneacetone)palladiumCatalystHCID 962WaterSolventHCID 8028TetrahydrofuranSolvent

Conditions

Temperature
80 °C

Procedure

To a solution of methyl 6-bromo-5-fluoropicolinate (1.0 equiv.) in THF and water (10:1, 0.1 M) was added 2,6-difluoro-4-methoxyphenylboronic acid (2.5 equiv.) and potassium fluoride (3.3 equiv.). The reaction was degassed with nitrogen, then Pd2(dba)3 (0.25 equiv.) and tri-tert-butylphosphine (0.5 equiv.) were added and the reaction was heated to 80° C. for one hour. LC/MS analysis indicated complete conversion of the starting material to product. The reaction was cooled to room temperature, then concentrated in vacuo and fused to silica gel. The crude product was purified by ISCO flash chromatography eluting with ethyl acetate and hexanes (0% to 30% ethyl acetate) to provide methyl 6-(2,6-difluoro-4-methoxyphenyl)-5-fluoropicolinate as a white solid in 85% yield. LC/MS=298.0 (M+H), Rt=0.89 min.

Workup

  1. customThe reaction was degassed with nitrogen
  2. temperatureThe reaction was cooled to room temperature
  3. concentrationconcentrated in vacuo
  4. customThe crude product was purified by ISCO flash chromatography
  5. washeluting with ethyl acetate and hexanes (0% to 30% ethyl acetate)

Sources & evidence

ORD record
ord-f12289236517459faab528343748fba3
Source dataset
uspto-grants-2015_11
Patent number
US09173883B2

Reaction notes

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