3,5-Dihydroxy-3-methylpentanoic acid methyl ester → 5-Bromo-3-hydroxy-3-methylpentanoic acid methyl ester

HRID 64662Notes

Reaction equation

HRID 64662 reaction equation
[CH3:1][O:2][C:3](=[O:11])[CH2:4][C:5]([OH:10])([CH3:9])[CH2:6][CH2:7]O.[Br-:12].C([P+](OC1C=CC=CC=1)(OC1C=CC=CC=1)OC1C=CC=CC=1)C1C=CC=CC=1>O1CCCC1>[CH3:1][O:2][C:3](=[O:11])[CH2:4][C:5]([OH:10])([CH3:9])[CH2:6][CH2:7][Br:12]

Participants

4

Reactant 2

HCID 135190693,5-Dihydroxy-3-methylpentanoic acid methyl esterHCID 20236928Benzyl triphenoxyphosphonium bromide

Product 1

HCID 135190735-Bromo-3-hydroxy-3-methylpentanoic acid methyl ester

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent2×

Procedure

To a solution of 3.00 g. (18.5 mmol) 3,5-dihydroxy-3-methylpentanoic acid methyl ester in 15 ml. anhydrous tetrahydrofuran is added a solution of 8.90 g. (18.5 mmol) benzyl triphenoxyphosphonium bromide in 10 ml. tetrahydrofuran and the reaction mixture is stirred for 15 hours at ambient temperature. Thereafter, it is evaporated in a vacuum, the bath temperature thereby being kept below 15° C. The oily residue obtained is chromatographed on 700 g. silica gel 60 with n-hexane/tert.-butanol (6:1 v/v) as elution agent. After removal of the elution agent, there is obtained 1.32 g. (32% of theory) of the desired product in the form of a bright yellow oil; nD20 =1.4734; RF =0.65 (silica gel; n-hexane/tert.-butanol (6:1 v/v)).

Workup

  1. customThereafter, it is evaporated in a vacuum
  2. customthereby being kept below 15° C
  3. customThe oily residue obtained
  4. customis chromatographed on 700 g
  5. washsilica gel 60 with n-hexane/tert.-butanol (6:1 v/v) as elution agent
  6. customAfter removal of the elution agent
  7. customthere is obtained 1.32 g

Sources & evidence

ORD record
ord-49603792b6eb43599ed4852cfc0b43b7
Source dataset
uspto-grants-1986_09
Patent number
US04609673

Reaction notes

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