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
Terminal alkynes add across α,β-unsaturated ketones in the presence of palladium catalysts. The reaction affords γ,δ-ynones.[4] Terminal alkynes add across epoxides to given yneols, which can be oxidized to give β,γ-ynones.[5]
Further reading
Bis-ynones can undergo an intramolecular
cycloaddition to form
furan derivatives.[6]
^Wang, Baomin; Bonin, Martine; Micouin, Laurent (June 22, 2005). "A Straightforward Synthesis of Ynones by Reaction of Dimethylalkynylaluminum Reagents with Acid Chlorides". J. Org. Chem.70 (15): 6126–6128.
doi:
10.1021/jo050760y.
PMID16018717.
^Weijiang, Sun; Wang, Yan; Wua, Xuan; Yao, Xiaoquan (2013). "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". Green Chemistry. 15 (9): 2356–2360.
doi:
10.1039/c3gc40980e.
^Wang, Zhaofeng; Li, Li; Yong, Huang (August 18, 2014). "A General Synthesis of Ynones from Aldehydes via Oxidative C–C bond Cleavage under Aerobic Conditions". J. Am. Chem. Soc.136 (35): 12233–12236.
doi:
10.1021/ja506352b.
PMID25133731.