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

HRID 887965Notes

Reaction equation

HRID 887965 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-3-tetrahydropyranyloxy-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−1): 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-1e355784ef0b48448dbe3d2fc40bfc0c
Source dataset
uspto-grants-2012_08
Patent number
US08247551B2

Reaction notes

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