Ethyl diazoacetate → Ethyl 3-(bromomethyl)-2-methyl-2-(3-nitrophenyl)cyclopropane Carboxylate

HRID 428902Notes

Reaction equation

HRID 428902 reaction equation
[Br:1][CH2:2]/[CH:3]=[C:4](/[C:6]1[CH:11]=[CH:10][CH:9]=[C:8]([N+:12]([O-:14])=[O:13])[CH:7]=1)\[CH3:5].[N+](=[CH:17][C:18]([O:20][CH2:21][CH3:22])=[O:19])=[N-]>ClCCl.CC(O)=O.CC(O)=O.CC(O)=O.CC(O)=O.[Rh].[Rh]>[Br:1][CH2:2][CH:3]1[CH:17]([C:18]([O:20][CH2:21][CH3:22])=[O:19])[C:4]1([CH3:5])[C:6]1[CH:11]=[CH:10][CH:9]=[C:8]([N+:12]([O-:14])=[O:13])[CH:7]=1

Participants

5

Reactant 2

HCID 12192Ethyl diazoacetateHCID 695548111-[(E)-3-bromo-1-methyl-1-propenyl]-3-nitrobenzene

Product 1

HCID 18359346Ethyl 3-(bromomethyl)-2-methyl-2-(3-nitrophenyl)cyclopropane CarboxylateYield 11%

Reagents, catalysts & solvents 2

HCID 423677Acetic acid, rhodium salt (4:2)CatalystHCID 6344DichloromethaneSolvent2×

Procedure

To a solution of 1-[(E)-3-bromo-1-methyl-1-propenyl]-3-nitrobenzene (Preparation 4, 4 g, 15.6 mmol) in dichloromethane (5 ml) was added rhodium (II) acetate dirner (100 mg, 0.22 nmnol). To the mixture was added dropwise at room temperature over 4.5 h a solution of ethyl diazoacetate (3.1 ml, 2.84 g, 25 mmol) in dichloromethane (15 ml). The mixture was filtered, concentrated in vacuo, and the residue purified by silica column (100 g) chromatography, eluting with 2:1 hexane/dichloromethane then dichloromethane. Product-containing fractions were combined and concentrated in vacuo, then purified further by preparative HPLC (Condition 1). Combination and evaporation of appropriate fractions gave the title compound as a colourless oil (0.5 g, 11%).

Workup

  1. filtrationThe mixture was filtered
  2. concentrationconcentrated in vacuo
  3. customthe residue purified by silica column (100 g) chromatography
  4. washeluting with 2:1 hexane/dichloromethane
  5. concentrationconcentrated in vacuo
  6. custompurified further by preparative HPLC (Condition 1)
  7. customCombination and evaporation of appropriate fractions

Sources & evidence

ORD record
ord-5fc387840c3c49da9510a75fc84009cf
Source dataset
uspto-grants-2001_11
Patent number
US06313312B1

Reaction notes

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