Ynone
{{Short description|1=Organic compounds of the form RC≡CC(=O)R’}}
In organic chemistry, an ynone is an organic compound containing a ketone ({{chem2|>C\dO}}) functional group and a {{chem2|C\tC}} triple bond. Many ynones are α,β-ynones, where the carbonyl and alkyne groups are conjugated. Capillin is a naturally occurring example. Some ynones are not conjugated.
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.{{cite journal |last1=Wang |first1=Baomin |last2=Bonin |first2=Martine |last3=Micouin |first3=Laurent |title=A Straightforward Synthesis of Ynones by Reaction of Dimethylalkynylaluminum Reagents with Acid Chlorides |journal=J. Org. Chem. |date=June 22, 2005 |volume=70 |issue=15 |pages=6126–6128 |doi=10.1021/jo050760y |pmid=16018717 }}
An alternative is the direct coupling of an acyl chloride with a terminal alkyne, using a copper-based nanocatalyst:{{cite journal |last1=Weijiang |first1=Sun |last2=Wang |first2=Yan |last3=Wua |first3=Xuan |last4=Yao |first4=Xiaoquan |title=Palladium-, ligand-, and solvent-free synthesis of ynones by the coupling of acyl chlorides and terminal alkynes in the presence of a reusable copper nanoparticle catalyst |journal=Green Chemistry |date=2013 |volume=15 |issue=9 |pages=2356–2360 |doi=10.1039/c3gc40980e }}
Other methods utilize an oxidative cleavage of an aldehyde, followed by reaction with a hypervalent alkynyl iodide, using a gold catalyst.{{cite journal |last1=Wang |first1=Zhaofeng |last2=Li |first2=Li |last3=Yong |first3=Huang |title=A General Synthesis of Ynones from Aldehydes via Oxidative C–C bond Cleavage under Aerobic Conditions |journal=J. Am. Chem. Soc. |date=August 18, 2014 |volume=136 |issue=35 |pages=12233–12236 |doi=10.1021/ja506352b |pmid=25133731 }}
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
Terminal alkynes add across α,β-unsaturated ketones in the presence of palladium catalysts. The reaction affords γ,δ-ynones.{{cite journal|doi=10.15227/orgsyn.091.0072|title=Palladium-catalyzed 1,4-Addition of Terminal Alkynes to Conjugated Enones|journal=Organic Syntheses|volume=91|pages=72|year=2014|author=Feng Zhou, Liang Chen, Chao-Jun Li|doi-access=free}} Terminal alkynes add across epoxides to given yneols, which can be oxidized to give β,γ-ynones.{{cite journal|doi=10.15227/orgsyn.084.0199|title=Electrophilic Cyclization with N-Iodosuccinimide: Preparation of 5-(4-Bromophenyl)-3-Iodo-2-(4-Methyl-Phenyl)Furan|journal=Organic Syntheses|volume=84|pages=199|year=2007|author=Adam Sniady, Marco S. Morreale, Roman Dembinski}}
Further reading
- Bis-ynones can undergo an intramolecular cycloaddition to form furan derivatives.{{cite journal |last1=Wills |first1=M.S.B. |authorlink2=Rick L. Danheiser|last2=Danheiser |first2=R.L. |title=Intramolecular [4 + 2] Cycloaddition Reactions of Conjugated Ynones. Formation of Polycyclic Furans via the Generation and Rearrangement of Strained Heterocyclic Allenes |journal=J. Am. Chem. Soc. |date=August 28, 1998 |volume=120 |issue=36 |pages=9378–9379 |doi=10.1021/ja9819209}}
See also
References
{{Reflist}}
External links
- {{Commonscatinline|Ynones}}
{{Functional group}}