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

HRID 749377Notes

Reaction equation

HRID 749377 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-1e7439a6e4174fe6a0e2a85e7b8da637
Source dataset
uspto-grants-2008_07
Patent number
US07402608B2

Reaction notes

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