16982-86-8Relevant articles and documents
NOVEL COMPOUNDS
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Page/Page column 62, (2022/03/22)
The invention relates to compounds of formula (I) and related aspects.
NOVEL COMPOUNDS
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Page/Page column 106, (2022/03/22)
The invention relates to compounds of formula (I): and related aspects.
Relay Catalysis by Achiral Borane and Chiral Phosphoric Acid in the Metal-Free Asymmetric Hydrogenation of Chromones
Chen, Jingjing,Gao, Bochao,Feng, Xiangqing,Meng, Wei,Du, Haifeng
, p. 8565 - 8569 (2021/11/13)
A strategy of relay catalysis by achiral borane and chiral phosphoric acid was successfully developed for the asymmetric hydrogenation of chromones, giving the desired products in high yields with up to 95% ee. Achiral borane and chiral phosphoric acid are highly compatible in this reaction. The achiral borane acts as a Lewis acid for the first-step hydrogenation, and the chiral phosphoric acid acts as an effective chiral proton shuttle to control the enantioselectivity.
Oxidant-Free Selective Synthesis of Functionalized Chroman-4-ones from ortho -Hydroxyacetophenones under HOAc/DMSO Conditions
Feng, Yuanyuan,Jiang, Tao-Shan,Li, Shuai,Shi, Xu,Wang, Anan
, (2022/02/10)
A metal-free and oxidant-free acid-promoted DMSO activation and subsequent reaction is reported. In this protocol, two molecules of DMSO are activated by HOAc and serve as dual synthons which react with ortho-hydroxyacetophenones, affording 3-(methylthiomethyl)chroman-4-ones in moderate to good yields with high selectivity.
Synthesis of Flavanones via Palladium(II)-Catalyzed One-Pot β-Arylation of Chromanones with Arylboronic Acids
Cho, Yang Yil,Jang, Hyu Jeong,Kim, Dong Hwan,Kim, Nam Yong,Kim, Nam-Jung,Kim, Young Min,Lee, Soo Jin,Lee, Yong Sup,Park, Boyoung Y.,Son, Seung Hwan,Yoo, Hyung-Seok
supporting information, p. 10012 - 10023 (2019/08/30)
A total of 47 flavanones were expediently synthesized via one-pot β-arylation of chromanones, a class of simple ketones possessing chemically unactivated β sites, with arylboronic acids via tandem palladium(II) catalysis. This reaction provides a novel route to various flavanones, including natural products such as naringenin trimethyl ether, in yields up to 92percent.
Cobalt-catalyzed cyclization with the introduction of cyano, acyl and aminoalkyl groups
Hori, Hiroto,Arai, Shigeru,Nishida, Atsushi
supporting information, p. 4783 - 4788 (2019/05/24)
An efficient synthesis of carbo-and heterocycles using CC, CO and CN bonds under cobalt catalysis is described. The substituents on olefins are key for controlling the regio-and chemoselectivity in the initial hydrogen atom transfer step and quaternary carbons are efficiently constructed under mild conditions. Cyclopropane cleavage and tandem cyclization give highly functionalized bicyclic skeletons in a single operation.
Generation of Phosphoranyl Radicals via Photoredox Catalysis Enables Voltage-Independent Activation of Strong C-O Bonds
Stache, Erin E.,Ertel, Alyssa B.,Rovis, Tomislav,Doyle, Abigail G.
, p. 11134 - 11139 (2018/11/21)
Despite the prevalence of alcohols and carboxylic acids as functional groups in organic molecules and the potential to serve as radical precursors, C-O bonds remain difficult to activate. We report a synthetic strategy for direct access to both alkyl and acyl radicals from these ubiquitous functional groups via photoredox catalysis. This method exploits the unique reactivity of phosphoranyl radicals, generated from a polar/SET crossover between a phosphine radical cation and an oxygen-centered nucleophile. We show the desired reactivity in the reduction of benzylic alcohols to the corresponding benzyl radicals with terminal H atom trapping to afford the deoxygenated products. Using the same method, we demonstrate access to synthetically versatile acyl radicals, which enables the reduction of aromatic and aliphatic carboxylic acids to the corresponding aldehydes with exceptional chemoselectivity. This protocol also transforms carboxylic acids to heterocycles and cyclic ketones via intramolecular acyl radical cyclizations to forge C-O, C-N, and C-C bonds in a single step.
Straightforward synthesis of functionalized chroman-4-ones through cascade radical cyclization-coupling of 2-(allyloxy)arylaldehydes
Zhao, Jingjing,Li, Pan,Li, Xinjian,Xia, Chungu,Li, Fuwei
, p. 3661 - 3664 (2016/03/05)
A novel and direct approach to synthesize a series of phosphonate, azide and hydroxy functionalized chroman-4-ones has been developed. The cascade transformation appears to proceed through an intramolecular addition of an in situ generated acyl radical onto the alkene, followed by a selective nucleophilic radical-electrophilic radical cross coupling.
Development of a chiral bis(guanidino)iminophosphorane as an uncharged organosuperbase for the enantioselective amination of ketones
Takeda, Tadahiro,Terada, Masahiro
supporting information, p. 15306 - 15309 (2013/11/06)
Chiral bis(guanidino)iminophosphoranes were designed and synthesized as chiral uncharged organosuperbase catalysts that facilitate activation of less-acidic pro-nucleophiles. The newly developed bis(guanidino) iminophosphoranes, which possess the highest basicity among chiral organocatalysts reported to date, were proven to be a superb class of chiral organosuperbases by reaction of azodicarboxylates with 2-alkyltetralones and their analogues as the less acidic pro-nucleophiles.
Intermolecular C-O addition of carboxylic acids to arynes: Synthesis of o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones
Dubrovskiy, Anton V.,Larock, Richard C.
, p. 2789 - 2798 (2013/03/29)
An efficient and simple route to biologically and pharmaceutically important o-hydroxyaryl ketones, xanthones, 4-chromanones, and flavones has been developed utilizing readily available carboxylic acids and commercially available o-(trimethylsilyl)aryl tr
