Ynone
Organic compounds of the form RC≡CC(=O)R′
From Wikipedia, the free encyclopedia
In organic chemistry, an ynone is an organic compound containing a ketone (>C=O) functional group and a C≡C triple bond. The simplest ynone is butynone.
Many ynones are α,β-ynones, where the carbonyl and alkyne groups are one bond apart, allowing them to form a conjugated system. Capillin is a natural example of a doubly conjugated ynone.
Non-conjugated ynones have additional sp3 carbon atoms between the carbonyl and alkyne groups which prevent conjugation.
Synthesis of α,β-ynones
One method for synthesizing ynones is the acyl substitution reaction of an alkynyldimethylaluminum with an acyl chloride. An alkynyldimethylaluminum compound is the reaction product of trimethylaluminum and a terminal alkyne.[1]
An alternative is the direct coupling of an acyl chloride with a terminal alkyne, using a copper-based nanocatalyst:[2]
Other methods utilize an oxidative cleavage of an aldehyde, followed by reaction with a hypervalent alkynyl iodide, using a gold catalyst.[3]
An alternative but longer synthetic method involves the reaction of an alkynyllithium compound with an aldehyde. The reaction produces a secondary alcohol that then can be oxidized via the Swern oxidation.
Synthesis of β,γ- and γ,δ-ynones
Further reading
- Bis-ynones can undergo an intramolecular cycloaddition to form furan derivatives.[6]
