Ethyl diazoacetate → 7-Hydroxy-6-propionyl-1,1a,2,7b-tetrahydro-cyclopropa[c]chromene-1-carboxylic acid ethyl ester

HRID 2182026Notes

Reaction equation

HRID 2182026 reaction equation
[OH:1][C:2]1[C:11]([C:12](=[O:15])[CH2:13][CH3:14])=[CH:10][CH:9]=[C:8]2[C:3]=1[CH:4]=[CH:5][CH2:6][O:7]2.[N+](=[CH:18][C:19]([O:21][CH2:22][CH3:23])=[O:20])=[N-]>ClCCCl>[CH2:22]([O:21][C:19]([CH:18]1[CH:4]2[CH:5]1[CH2:6][O:7][C:8]1[CH:9]=[CH:10][C:11]([C:12](=[O:15])[CH2:13][CH3:14])=[C:2]([OH:1])[C:3]=12)=[O:20])[CH3:23]

Participants

4

Reactant 2

HCID 12192Ethyl diazoacetateHCID 224828711-(5-hydroxy-2H-chromen-6-yl)-propan-1-one

Product 1

HCID 213049647-Hydroxy-6-propionyl-1,1a,2,7b-tetrahydro-cyclopropa[c]chromene-1-carboxylic acid ethyl esterYield 41.3%

Reagents, catalysts & solvents 1

HCID 111,2-DichloroethaneSolvent2×

Procedure

To a mixture of 1-(5-hydroxy-2H-chromen-6-yl)-propan-1-one (511 mg, 2.5 mmol) and (Rh(II)Ac2)2 (11 mg, 0.025 mmol) in 1,2-dichloroethane (8 mL) at 20° C., was added dropwise (3 h) a solution of ethyl diazoacetate (571 mg, 5 mmol) in 1,2-dichloroethane (2 mL). After 15 min at 20° C., the reaction mixture was washed with H2O (10 mL). The H2O phase was washed with CH2Cl2 (10 mL) and the solvent of the combined organic phases was removed under reduced pressure. The crude product was purified by column chromatography (silica gel, 1→5% MeOH in CH2Cl2), to give 300 mg (41%) of 7-hydroxy-6-propionyl-1,1a,2,7b-tetrahydro-cyclopropa[c]chromene-1-carboxylic acid ethyl ester (a 33/64 mixture of cis and trans isomers).

Workup

  1. washthe reaction mixture was washed with H2O (10 mL)
  2. washThe H2O phase was washed with CH2Cl2 (10 mL)
  3. customthe solvent of the combined organic phases was removed under reduced pressure
  4. customThe crude product was purified by column chromatography (silica gel, 1→5% MeOH in CH2Cl2)

Sources & evidence

ORD record
ord-6888159d71584da3928a4019d0006ff8
Source dataset
uspto-grants-2005_05
Patent number
US06894177B2

Reaction notes

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