1,2-Dibromoethane → (2S,4R)-2-Methyl-4-(thiophen-3-yl)oxan-4-ol

HRID 1729390Notes

Reaction equation

HRID 1729390 reaction equation
BrCCBr.[Mg].Br[C:7]1[CH:11]=[CH:10][S:9][CH:8]=1.[CH3:12][C@H:13]1[CH2:18][C:17](=[O:19])[CH2:16][CH2:15][O:14]1>C(OCC)C>[OH:19][C@:17]1([C:7]2[CH:11]=[CH:10][S:9][CH:8]=2)[CH2:16][CH2:15][O:14][C@@H:13]([CH3:12])[CH2:18]1

Participants

6

Reactant 4

HCID 78391,2-Dibromoethane2×HCID 133833-BromothiopheneHCID 5462224MagnesiumHCID 10125057(2S)-2-Methyloxan-4-one

Product 1

HCID 53991311(2S,4R)-2-Methyl-4-(thiophen-3-yl)oxan-4-olYield 19.7%

Reagents, catalysts & solvents 1

HCID 3283Diethyl EtherSolvent4×

Procedure

A solution of 1,2-dibromoethane (5 g) in diethyl ether (10 ml) was added to a stirred suspension of magnesium (3 g) in diethyl ether (10 ml) to initiate the formation of a Grignard reagent. A mixture of 1,2-dibromoethane (16.7 g) and 3-bromothiophene (4 g) in diethyl ether (30 ml) was added dropwise. The mixture was stirred and heated to reflux for 2 hours. A solution of (2S)-2-methyltetrahydropyran-4-one (2 g) in diethyl ether (5 ml) was added and the mixture was heated to reflux for 1 hour. The mixture was partitioned between ethyl acetate and water. The organic phase was dried (MgSO4) and evaporated. The residue was purified by column chromatography using a 7:3 mixture of petroleum ether and ethyl acetate as eluent. There were thus obtained in turn (2S,4R)-4-hydroxy-2-methyl-4-(3-thienyl)tetrahydropyran (0.685 g, 18.5%) and the corresponding (2S,4S)-isomer (1 g, 32%).

Workup

  1. additionwas added dropwise
  2. temperatureheated
  3. temperatureto reflux for 2 hours
  4. temperaturethe mixture was heated
  5. temperatureto reflux for 1 hour
  6. customThe mixture was partitioned between ethyl acetate and water
  7. dry with materialThe organic phase was dried (MgSO4)
  8. customevaporated
  9. customThe residue was purified by column chromatography
  10. additiona 7:3 mixture of petroleum ether and ethyl acetate as eluent

Sources & evidence

ORD record
ord-52e54b37e3084ccf83124e8d56ca913b
Source dataset
uspto-grants-1994_07
Patent number
US05332757

Reaction notes

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