Hydrochloric Acid → 1-(2,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-yl)ethan-1-one

HRID 898667Notes

Reaction equation

HRID 898667 reaction equation
Br[C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[CH2:6][C:5]2([CH3:15])[CH3:14].C([Sn](CCCC)(CCCC)[C:21]([O:23]CC)=[CH2:22])CCC.Cl>C(OCC)(=O)C.CCCCCC.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1>[C:21]([C:2]1[CH:3]=[C:4]2[C:9](=[CH:10][CH:11]=1)[O:8][C:7]([CH3:13])([CH3:12])[CH2:6][C:5]2([CH3:15])[CH3:14])(=[O:23])[CH3:22]

Participants

7

Reactant 3

HCID 313Hydrochloric AcidHCID 619414Stannane, tributyl(1-ethoxyethenyl)-HCID 121370056-Bromo-2,2,4,4-tetramethylchroman

Product 1

HCID 156611361-(2,2,4,4-Tetramethyl-3,4-dihydro-2H-1-benzopyran-6-yl)ethan-1-oneYield 46%

Reagents, catalysts & solvents 3

HCID 178418476HCID 178418476, compoundCatalystHCID 8058HexaneSolventHCID 8857Ethyl AcetateSolvent2×

Conditions

Temperature
80 °C

Procedure

A solution of 6-bromo-2,2,4,4-tetramethyl chroman (see U.S. Pat. No. 6,252,090, 0.9 g, 3.34 mmol) in anhydrous tetrahydrofuran (50 mL) was sparged with argon for 5 min. and treated with dichlorobis(triphenylphosphine)palladium(II) (0.117 g, 0.167 mmol) followed by tributyl(1-ethoxyvinyl)tin (2.41 g, 6.7 mmol). The resulting reaction mixture was heated at 80° C. under argon for 18 h. The reaction mixture was then cooled to ambient temperature and treated with 10% aqueous hydrochloric acid (5 mL) and stirred for 30 min. The reaction mixture was then diluted with ethyl acetate and washed with water (×1) and brine (×1). The organic phase was dried over anhydrous sodium sulfate, filtered and evaporated in vacuo to afford a residue that was subjected to flash column chromatography over silica gel (230-400 mesh) using 2-3%% ethyl acetate in hexane as the eluent to afford the title compound as a colorless oil (0.36 g, 46%).

Workup

  1. custom6,252,090, 0.9 g, 3.34 mmol) in anhydrous tetrahydrofuran (50 mL) was sparged with argon for 5 min.
  2. customThe resulting reaction mixture
  3. temperatureThe reaction mixture was then cooled to ambient temperature
  4. washwashed with water (×1) and brine (×1)
  5. dry with materialThe organic phase was dried over anhydrous sodium sulfate
  6. filtrationfiltered
  7. customevaporated in vacuo
  8. customto afford a residue that

Sources & evidence

ORD record
ord-b748db54bd4840f9951033eee0dd76e3
Source dataset
uspto-grants-2008_04
Patent number
US07351737B2

Reaction notes

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