Sodium borohydride → 6'-Bromo-4-hydroxyspiro[cyclohexane-1,2'-inden]-1'(3'H)-one

HRID 1770875Notes

Reaction equation

HRID 1770875 reaction equation
[Br:1][C:2]1[CH:10]=[C:9]2[C:5]([CH2:6][C:7]3([CH2:16][CH2:15][C:14](=[O:17])[CH2:13][CH2:12]3)[C:8]2=[O:11])=[CH:4][CH:3]=1.[BH4-].[Na+]>C1COCC1>[Br:1][C:2]1[CH:10]=[C:9]2[C:5]([CH2:6][C:7]3([CH2:16][CH2:15][CH:14]([OH:17])[CH2:13][CH2:12]3)[C:8]2=[O:11])=[CH:4][CH:3]=1

Participants

4

Reactant 2

HCID 4311764Sodium borohydrideHCID 581972056'-Bromospiro[cyclohexane-1,2'-indene]-1',4(3'H)-dione3×

Product 1

HCID 581970336'-Bromo-4-hydroxyspiro[cyclohexane-1,2'-inden]-1'(3'H)-oneYield 221.5%

Reagents, catalysts & solvents 1

HCID 8028TetrahydrofuranSolvent

Conditions

Temperature
-65 °C

Procedure

6′-Bromospiro[cyclohexane-1,2′-indene]-1′,4(3′H)-dione (Intermediate 5 Step 1, 6.1 g, 20.8 mmol) was dissolved in THF (220 mL) and cooled to −65° C. Sodium borohydride (0.354 g, 9.36 mmol) was added and the cooling bath was removed. The mixture was allowed to reach 0° C. (approx. 30 min). Water (10 mL) was added, and most of the organic solvent was removed by evaporation. The residue was partitioned between EtOAc (100 mL), and an aq. solution of NaCl (50 mL). The organic phase was dried (MgSO4) and evaporated to give a product which was combined with additional product obtained in a similar way starting from 14.6 g of 6′-bromospiro[cyclohexane-1,2′-indene]-1′,4(3′H)-dione. Purification was made by flash chromatography (120 g silica, gradient elution: CH2Cl2 to CH2Cl2/MeOH (90:10)) affording 13.6 g (66% yield) of the title compound. The obtained material consisted of an 80:20 mixture of isomer 1 and isomer 2. Analytical samples of the isomers were isolated by flash chromatography (heptane/EtOAc gradient) to yield:

Workup

  1. customthe cooling bath was removed
  2. customto reach 0° C.
  3. custom(approx. 30 min)
  4. additionWater (10 mL) was added
  5. custommost of the organic solvent was removed by evaporation
  6. customThe residue was partitioned between EtOAc (100 mL)
  7. dry with materialThe organic phase was dried (MgSO4)
  8. customevaporated
  9. customto give a product which
  10. customobtained in a similar way
  11. customPurification
  12. washwas made by flash chromatography (120 g silica, gradient elution: CH2Cl2 to CH2Cl2/MeOH (90:10))

Sources & evidence

ORD record
ord-b46cad931ed14c938fb6e54cb4b54b0d
Source dataset
uspto-grants-2016_02
Patent number
US09248129B2

Reaction notes

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