Ynone
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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.
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]
