Methyl iodide → 2,6-Octadienoic acid, 3,7-dimethyl-, methyl ester, (2Z)-
Reaction equation
CI.N1CCOC[CH2:4]1.[CH3:9][C:10]([CH3:20])=[CH:11][CH2:12][CH2:13][C:14]#[C:15][C:16]([O:18][CH3:19])=[O:17].C(C(CC=C(C)C)C(OC)=O)(=O)C>>[CH3:4]/[C:14](/[CH2:13][CH2:12][CH:11]=[C:10]([CH3:20])[CH3:9])=[CH:15]/[C:16]([O:18][CH3:19])=[O:17]Participants
Procedure
The overall process can be illustrated by the manufacture of nerol, ((Z)-3,7-dimethylocta-2,6-dien-1-ol), which begins with the treatment of 2-butynoic acid with lithium 2,2,6,6-tetramethylpiperidide, followed by alkylation with 1-bromo-3-methyl-2-butene to yield 7-methyloct-6-en-2-ynoic acid as the major product. 2-Ethenylidene-5-methyl-4-hexenoic acid is produced as a minor product in the course of the alkylation. The acids are esterified conveniently with methyl iodide, and treated with morpholine, followed by acid workup, to give a mixture of a major amount of methyl 7-methyloct-6-en-2-ynoate and a minor amount of methyl 2-acetyl-5-methyl-4-hexenoate. The latter compounds are separated by chromatography on a silica gel column using ethyl acetate-n-hexane as eluant. Contacting of the isolated methyl 7-methyloct-6-en-2-ynoate with a mixture of lithium dimethyl cuprate and methyl copper at low temperatures gives methyl (Z)-3,7-dimethylocta-2,6-dienoate, which is reduced to nerol, (Z)-3,7-dimethylocta-2,6-dien-1-ol, for example, with aluminium hydride.
Workup
- customto give
- customThe latter compounds are separated by chromatography on a silica gel column
- additionContacting of the isolated methyl 7-methyloct-6-en-2-ynoate with a mixture of lithium dimethyl cuprate and methyl copper at low temperatures
Sources & evidence
- ORD record
- ord-834c83da47944ff4ab31878df934950f
- Source dataset
- uspto-grants-1976_07
- Patent number
- US03971827
Reaction notes
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