6-Bromo-2,2-dimethyl-2H-chromene → 2,2-Dimethyl-6-phenylsulfanyl-2H-chromene

HRID 1159625Notes

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])[CH:6]=[CH:5]2.C([Li])CCC.[CH:19]12S[CH:20]1[CH:21]1[S:25][CH:22]1[CH:23]=[CH:24]2>C1COCC1>[CH3:12][C:7]1([CH3:13])[CH:6]=[CH:5][C:4]2[C:9](=[CH:10][CH:11]=[C:2]([S:25][C:22]3[CH:23]=[CH:24][CH:19]=[CH:20][CH:21]=3)[CH:3]=2)[O:8]1

Participants

Conditions

Temperature: -78 °C

Procedure

6-Bromo-2,2-dimethyl-2H-chromene (10 mmoL) in THF (20 mL) was treated with n-butyl lithium (15 mmoL) dropwise at −78° C. The resulting solution was stirred at −78° C. for 30 min. Benzene disulfide (10 mmoL) in THF (10 mL) was then added dropwise into the reaction over about 15 min. The reaction mixture was kept at −78° C. and slowly warmed to room temperature over 2 hrs. The solvent was removed and the residue was partitioned between diethyl ether and water. The combined organic layer was washed with brine, filtered, dried over anhydrous Na2SO4 and concentrated to yield crude material, which was purified by silica gel chromatography to yield the title compound as a white solid.

Workup

customwas kept at −78° C.
temperatureslowly warmed to room temperature over 2 hrs
customThe solvent was removed
customthe residue was partitioned between diethyl ether and water
washThe combined organic layer was washed with brine
filtrationfiltered
dry with materialdried over anhydrous Na2SO4
concentrationconcentrated
customto yield crude material, which
customwas purified by silica gel chromatography

Sources & evidence

ORD record: ord-c252170d81594bea9745d65e9aabfa23
Source dataset: uspto-grants-2010_10
DOI: 10.6084/m9.figshare.5104873.v1
Patent number: US07812183B2

Reaction notes

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