Diethyl Oxalate → ethyl 5-methyl-2-oxo-5-(tetrahydro-2H-pyran-2-yloxy)hex-3-ynoate

HRID 1365075Notes

Reaction equation

HRID 1365075 reaction equation
C([Li])CCC.[CH3:6][C:7]([O:11][CH:12]1[CH2:17][CH2:16][CH2:15][CH2:14][O:13]1)([CH3:10])[C:8]#[CH:9].[C:18](OCC)(=[O:24])[C:19]([O:21][CH2:22][CH3:23])=[O:20].[NH4+].[Cl-]>CCCCCC.CCOCC.CCCCCC.CCOC(C)=O>[CH3:10][C:7]([O:11][CH:12]1[CH2:17][CH2:16][CH2:15][CH2:14][O:13]1)([CH3:6])[C:8]#[C:9][C:18](=[O:24])[C:19]([O:21][CH2:22][CH3:23])=[O:20]

Participants

8

Reactant 4

HCID 7268Diethyl OxalateHCID 25517Ammonium ChlorideHCID 41938432-Methyl-3-butyn-2-yl 2-tetrahydropyranyl etherHCID 178418339Butyllithium

Product 1

HCID 66940551ethyl 5-methyl-2-oxo-5-(tetrahydro-2H-pyran-2-yloxy)hex-3-ynoate

Reagents, catalysts & solvents 3

HCID 3283Diethyl EtherSolventHCID 8058HexaneSolventHCID 21226206Ethyl acetate hexaneSolvent

Conditions

Temperature
0 °C

Procedure

n-Butyl lithium (18 mL, of a 1.6 M solution in hexane, 28 mmol) was added to a solution of 3-methyl-3tetrahydropyranyloxy-butyne (3.3 g, 19 mmol) in Et2O, previously cooled at 0° C. The resulting solution was stirred for 30 min at 0° C., then cooled to −78° C. and diethyl oxalate (4.3 mL, 29.4 mmol) was added. The reaction was followed by TLC (hexane/AcOEt 90:10). After ca. 2 h the reaction mixture was poured in a cold aqueous solution of NH4Cl. The aqueous layer was extracted with of Et2O (3×25 mL). The organics were dried over MgSO4, the solvent was removed under reduced pressure and the resulting pale yellow oil was purified by chromatography (silica gel, hexane/AcOEt 90:10) to give ethyl 5-methyl-2-oxo-5-(tetrahydro-2H-pyran-2-yloxy)hex-3-ynoate (2) as a pale yellow liquid. Yield: 2.04 g (40%). 1H-NMR spectrum in CDCl3 (ppm): 5.10 (m, 1H), 4.38 (q, 2H), 4.36 (m, 2H), 3.96 (m, 2H), 3.54 (m, 2H), 1.85 (m, 2H), 1.75 (m, 2H), 1.64 (s, 3H), 1.59 (s, 3H), 1.40 (t, 3H). 13C-NMR spectrum in CDCl3 (ppm): 169.3, 158.7, 101.4, 96.2, 81.6, 70.5, 63.1, 31.5, 29.2, 28.9, 25.2, 19.9, 13.8, 13.8. Selected IR (neat, cm−): 2209, 1741, 1689. MS-APCI calculated for C14H20O5 [M]− 268.13. found 267.96.

Workup

  1. temperaturecooled to −78° C.
  2. extractionThe aqueous layer was extracted with of Et2O (3×25 mL)
  3. dry with materialThe organics were dried over MgSO4
  4. customthe solvent was removed under reduced pressure
  5. customthe resulting pale yellow oil was purified by chromatography (silica gel, hexane/AcOEt 90:10)

Sources & evidence

ORD record
ord-ddd6fe8bde4f4783993fd11c815c9843
Source dataset
uspto-grants-2011_02
Patent number
US07888506B2

Reaction notes

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