Dichloromethane → [(1-Benzopyran-4-yloxy)methyl]acetic Acid Ethyl Ester

HRID 18832

Reaction equation

HRID 18832 reaction equation
[O:1]1[C:10]2[C:5](=[CH:6][CH:7]=[CH:8][CH:9]=2)[CH:4]([OH:11])[CH2:3][CH2:2]1.[N+](=[CH:14][C:15]([O:17][CH2:18][CH3:19])=[O:16])=[N-].Cl[CH2:21]Cl>CCCCCCC.CC(O)=O.CC(O)=O.CC(O)=O.CC(O)=O.[Rh].[Rh]>[CH2:18]([O:17][C:15](=[O:16])[CH2:14][CH2:21][O:11][C:4]1[C:5]2[CH:6]=[CH:7][CH:8]=[CH:9][C:10]=2[O:1][CH2:2][CH:3]=1)[CH3:19]

Participants

6

Reactant 3

HCID 6344DichloromethaneHCID 12192Ethyl diazoacetateHCID 92890Chroman-4-ol

Product 1

HCID 68569392[(1-Benzopyran-4-yloxy)methyl]acetic Acid Ethyl Ester

Reagents, catalysts & solvents 2

HCID 423677Acetic acid, rhodium salt (4:2)CatalystHCID 8900HeptaneSolvent

Procedure

To a solution of 4-chromanol (1.5 g, 10.0 mmol) in dichloromethane (20 mL) is added rhodium (II) acetate dimer (10 mg) followed by ethyl diazoacetate (0.95 mL, 9.0 mmol). The reaction mixture is stirred at rt for 30 min. The reaction mixture is diluted with heptane, filtered through Celite, and the filtrate is evaporated and the residue purified by chromatography on silica gel; elution with EtOAc:dichloromethane:hexane (10:20:70) gives 1.81 g of the product 475. 1H NMR (CDCl3) δ 7.35 (dd, 1H), 7.22 (dt, 1H), 6.90 (t, 1H), 6.84 (d, 1H), 4.56 (m, 1H), 4.36 (dd, 1H), 4.29 (dd, 1H), 4.23 (q, 2H), 4.19 (s, 2H), 2.18 (m, 1H), 2.05 (m, 1H), 1.30 (t, 3H); MS: m/z 236 (M++1).

Workup

  1. filtrationfiltered through Celite
  2. customthe filtrate is evaporated
  3. customthe residue purified by chromatography on silica gel
  4. washelution with EtOAc:dichloromethane:hexane (10:20:70)

Sources & evidence

ORD record
ord-610fe69eecf9401499714223ef20c5b1
Source dataset
uspto-grants-2010_06
Patent number
US07741493B2

Linked notes

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