2-Butynoic acid → HCID 12456226, compound
Reaction equation
[OH:1][CH2:2]/[CH:3]=[C:4](/C)\[CH2:5][CH2:6][CH:7]=[C:8]([CH3:10])[CH3:9].C(O)(=[O:16])C#CC.[Li]N1C(C)(C)CCCC1(C)C.BrCC=C(C)C>>[CH3:9][C:8]([CH3:10])=[CH:7][CH2:6][CH2:5][C:4]#[C:3][C:2]([OH:1])=[O:16]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.
Sources & evidence
- ORD record
- ord-2d84e64da31940d4a0bdaf021aa833e6
- Source dataset
- uspto-grants-1976_07
- Patent number
- US03971827
Reaction notes
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