2-(2-Methyl-allyloxy)-pent-4-enoic acid ethyl ester → 5-methyl-3,6-dihydro-2H-pyran-2-carboxylic acid ethyl ester

HRID 73201Notes

Reaction equation

HRID 73201 reaction equation
[CH2:1]([O:3][C:4](=[O:14])[CH:5]([O:9][CH2:10][C:11]([CH3:13])=[CH2:12])[CH2:6]C=C)[CH3:2]>C(Cl)Cl>[CH2:1]([O:3][C:4]([CH:5]1[CH2:6][CH:13]=[C:11]([CH3:12])[CH2:10][O:9]1)=[O:14])[CH3:2]

Participants

3

Reactant 1

HCID 597523452-(2-Methyl-allyloxy)-pent-4-enoic acid ethyl ester

Product 1

HCID 597523065-methyl-3,6-dihydro-2H-pyran-2-carboxylic acid ethyl esterYield 94%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent2×

Procedure

To a refluxing stirred solution of 2-(2-methyl-allyloxy)-pent-4-enoic acid ethyl ester (396 mg, 2.0 mmol) in CH2Cl2 (100 mL, 0.02 M solution) was added drop wise a solution of the tricyclohexylphosphine (1,3-Bis(2,4,6-trimethylphenyl)-4,5-dihydroimidazol-2-ylidene)(benzylidine)ruthenium (IV)dichloride (85 mg, 0.1 mmol) in CH2Cl2 (3.0 mL). After 50 min, the reaction mixture was cooled to room temperature, concentrated and purified on silica gel bond elute using EtOAc/hexane (1:20) as an eluent furnished 5-methyl-3,6-dihydro-2H-pyran-2-carboxylic acid ethyl ester (320 mg, 92% yield) as a brown oil. NMR 1H (CDCl3, 400 MHz): 5.51 (br s, 1H), 4.28-4.08 (m, 4H), 2.32 (brs, 3H), 1.29 (t, J=7.2, 3H).

Workup

  1. concentrationconcentrated
  2. custompurified on silica gel bond
  3. washelute

Sources & evidence

ORD record
ord-ffb0c62ec54742ccaa769c9e5a7efa11
Source dataset
uspto-grants-2014_09
Patent number
US08829030B2

Reaction notes

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