Methanol → 2-((5-Methyl-2-(1-methylethyl)cyclohexyl)oxy)acetic acid
Reaction equation
CC(=[O:5])CC.[CH3:6][CH:7]1[CH2:12][CH:11]([O:13][CH2:14][C:15](Cl)=[O:16])[CH:10]([CH:18]([CH3:20])[CH3:19])[CH2:9][CH2:8]1.CO>N1C=CC=CC=1.Cl[Pd](Cl)([P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1)[P](C1C=CC=CC=1)(C1C=CC=CC=1)C1C=CC=CC=1.C1COCC1>[CH3:6][CH:7]1[CH2:12][CH:11]([O:13][CH2:14][C:15]([OH:5])=[O:16])[CH:10]([CH:18]([CH3:20])[CH3:19])[CH2:9][CH2:8]1Participants
Conditions
- Temperature
- 100 °C
Procedure
2-L-menthoxyacetyloxy-2-butene is prepared from 2-butanone, L-menthoxyacetyl chloride, and pyridine catalyst. A 70 mL stainless steel high pressure reactor fitted with a Pyrex glass liner and magnetic stir bar is charged with THF (5 mL), (PPh3)2PdCl2 (0.05 mmol), CH3OH (0.5 mmol), and 2-L-menthoxyacetyloxy-2-butene (0.5 mmol). The reactor is sealed, pressurized to 1000 psig with CO, and stirred for 24 hours at 100° C. The product mixture, isolated after removal of gas from the reactor vessel, contains a diastereomeric mixture of methyl 2-L-menthoxyacetyloxy-L-2-methylbutyrate and methyl 2-L-menthoxyacetyl-D-2-methylbutyrate. The diastereomers are separated by preparative gas chromatography using an SE-30 liquid phase column. Each diastereomer is hydrolyzed separately by treatment with 2N HCl (aq) for 2 hours at 100° C. to give pure L- and D-2-methyl-2-hydroxybutyric acid, methanol, and L-menthoxyacetic acid.
Workup
- customA 70 mL stainless steel high pressure reactor fitted with a Pyrex glass liner and magnetic stir bar
- customThe reactor is sealed
- customThe product mixture, isolated
- customafter removal of gas from the reactor vessel
- additiona diastereomeric mixture of methyl 2-L-menthoxyacetyloxy-L-2-methylbutyrate and methyl 2-L-menthoxyacetyl-D-2-methylbutyrate
- customThe diastereomers are separated by preparative gas chromatography
- waitEach diastereomer is hydrolyzed separately by treatment with 2N HCl (aq) for 2 hours at 100° C.
Sources & evidence
- ORD record
- ord-afb831407df4430886a27cb789777638
- Source dataset
- uspto-grants-1994_06
- Patent number
- US05324856
Reaction notes
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