23517-42-2Relevant articles and documents
Transformations of Aryl Ketones via Ligand-Promoted C?C Bond Activation
Dai, Hui-Xiong,Li, Hanyuan,Li, Ling-Jun,Liu, Qi-Sheng,Ma, Biao,Wang, Mei-Ling,Wang, Xing,Wang, Zhen-Yu,Xu, Hui
supporting information, p. 14388 - 14393 (2020/07/06)
The coupling of aromatic electrophiles (aryl halides, aryl ethers, aryl acids, aryl nitriles etc.) with nucleophiles is a core methodology for the synthesis of aryl compounds. Transformations of aryl ketones in an analogous manner via carbon–carbon bond activation could greatly expand the toolbox for the synthesis of aryl compounds due to the abundance of aryl ketones. An exploratory study of this approach is typically based on carbon–carbon cleavage triggered by ring-strain release and chelation assistance, and the products are also limited to a specific structural motif. Here we report a ligand-promoted β-carbon elimination strategy to activate the carbon–carbon bonds, which results in a range of transformations of aryl ketones, leading to useful aryl borates, and also to biaryls, aryl nitriles, and aryl alkenes. The use of a pyridine-oxazoline ligand is crucial for this catalytic transformation. A gram-scale borylation reaction of an aryl ketone via a simple one-pot operation is reported. The potential utility of this strategy is also demonstrated by the late-stage diversification of drug molecules probenecid, adapalene, and desoxyestrone, the fragrance tonalid as well as the natural product apocynin.
Stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via a Beckmann rearrangement facilitated by diphenyl phosphorazidate
Ishihara, Kotaro,Shioiri, Takayuki,Matsugi, Masato
supporting information, p. 1295 - 1298 (2019/04/13)
A novel method for the stereospecific synthesis of 1,5-disubstituted tetrazoles from ketoximes via the Beckmann rearrangement was developed using diphenyl phosphorazidate (DPPA) as both the oxime activator and azide source. Various ketoximes were transformed into the corresponding 1,5-disubstituted tetrazoles with exclusive trans-group migration and no E-Z isomerization of the ketoxime. This method enables the preparation of 1,5-disubstituted tetrazoles without using toxic or explosive azidation reagents.
Dichloroimidazolidinedione-Activated Beckmann Rearrangement of Ketoximes for Accessing Amides and Lactams
Gao, Yu,Liu, Jingjing,Li, Zhenjiang,Guo, Tianfo,Xu, Songquan,Zhu, Hui,Wei, Fulan,Chen, Siming,Gebru, Hailemariam,Guo, Kai
, p. 2040 - 2049 (2018/02/23)
A novel protocol for the activation of the Beckmann rearrangement utilizing the readily available and economical geminal dichloroimidazolidinediones (DCIDs) on a substoichiometric scale (10 mol %) has been developed. A unique self-propagating mechanism for the substoichiometric dichloroimidazolidinedione-activated transformation was proposed and validated. The substrate scope of the developed protocol has been demonstrated by 23 examples with good to excellent yields (mostly 90-98%) in a short time (mostly 10-30 min), including a substrate for synthesizing the monomer of nylon-12 and a complicated steroidal substrate on a preparative scale. This research not only unveils for the first time the synthetic potential of substoichiometric amounts of dichloroimidazolidinediones in promoting chemical transformation but also offers yet another important illustration of the self-propagating cycle in the context of the Beckmann rearrangement activated by a structurally novel organic promoter.
