36920-29-3Relevant academic research and scientific papers
Platinum-Catalyzed α,β-Desaturation of Cyclic Ketones through Direct Metal–Enolate Formation
Chen, Ming,Dong, Guangbin
supporting information, p. 7956 - 7961 (2021/03/01)
The development of a platinum-catalyzed desaturation of cyclic ketones to their conjugated α,β-unsaturated counterparts is reported in this full article. A unique diene-platinum complex was identified to be an efficient catalyst, which enables direct metal-enolate formation. The reaction operates under mild conditions without using strong bases or acids. Good to excellent yields can be achieved for diverse and complex scaffolds. A wide range of functional groups, including those sensitive to acids, bases/nucleophiles, or palladium species, are tolerated, which represents a distinct feature from other known desaturation methods. Mechanistically, this platinum catalysis exhibits a fast and reversible α-deprotonation followed by a rate-determining β-hydrogen elimination process, which is different from the prior Pd-catalyzed desaturation method. Promising preliminary enantioselective desaturation using a chiral-diene-platinum complex has also been obtained.
Copper-Catalyzed Desaturation of Lactones, Lactams, and Ketones under pH-Neutral Conditions
Chen, Ming,Dong, Guangbin
supporting information, p. 14889 - 14897 (2019/10/02)
A copper-catalyzed desaturation method that is suitable for converting lactones, lactams, and cyclic ketones to their α,β-unsaturated counterparts is reported. The reaction does not require strong base/acid or sulfur/selenium reagents and can be carried out through a simple one-step operation. The protocol uses inexpensive catalysts and reagents and exhibits excellent scalability and functional group tolerance. Notably, tert-butyl alcohol is the only stoichiometric byproduct produced, and overoxidation is not observed. The reaction mechanism has been investigated through control experiments, deuterium labeling, radical clock, electron paramagnetic resonance, high-resolution mass spectrometry, and kinetic studies. The data obtained are consistent with a reaction pathway involving reversible α-deprotonation by a Cu(II)-OtBu species followed by further oxidation of the resulting Cu enolate.
Palladium-Catalyzed α-Arylation of Vinylogous Esters for the Synthesis of γ,γ-Disubstituted Cyclohexenones
Johnson, Thomas,Pultar, Felix,Menke, Friedericke,Lautens, Mark
, p. 6488 - 6491 (2016/12/23)
A palladium-catalyzed α-arylation of cyclic vinylogous esters to form products that are converted in one step to γ-alkyl-γ-aryl-substituted cyclohexenones is reported. This Pd-catalyzed reaction proceeds at room temperature, is generally high-yielding, and uses an amount of a commercially available catalyst as low as 0.25 mol %. The scope of aryl bromides is particularly broad, and alkenyl bromides can also be used. This two-step protocol, comprising α-arylation and reductive transposition, can be performed in one pot and is applicable to gram-scale synthesis.
An expedient protocol for cyclopentenone annulation
Kulkarni, Mukund G.,Davawala, Saryu I.,Doke, Aniruddha K.,Pendharkar, Dhananjay S.
, p. 2919 - 2926 (2007/10/03)
A convenient and general protocol for the cyclopentenone annulation process is described.
A simple strategy for spirocyclopentannulation of cyclic ketones. Formal total synthesis of (±)-acorone
Srikrishna, Adusumilli,Kumar, P. Praveen,Viswajanani, Ranganathan
, p. 1683 - 1686 (2007/10/03)
A general and simple methodology for spirocyclopentannulation of cyclic ketones (or 4,4-disubstituted cyclopentenones from acyclic ketones) and its application in the synthesis of the spirodienone 7 via a prochiral precursor constituting a formal total synthesis of (±)-acorone (6), are described.
