54313-85-8Relevant academic research and scientific papers
Site-Selective Pd-Catalyzed C(sp3)?H Arylation of Heteroaromatic Ketones
Kudashev, Anton,Baudoin, Olivier
supporting information, p. 17688 - 17694 (2021/11/16)
A ligand-controlled site-selective C(sp3)?H arylation of heteroaromatic ketones has been developed using Pd catalysis. The reaction occurred selectively at the α- or β-position of the ketone side-chain. The switch from α- to β-arylation was realized by addition of a pyridone ligand. The α-arylation process showed broad scope and high site- and chemoselectivity, whereas the β-arylation was more limited. Mechanistic investigations suggested that α-arylation occurs through C?H activation/oxidative addition/reductive elimination whereas β-arylation involves desaturation and aryl insertion.
Light-Driven Enantioselective Synthesis of Pyrroline Derivatives by a Radical/Polar Cascade Reaction
Rodríguez, Ricardo I.,Mollari, Leonardo,Alemán, José
, p. 4555 - 4560 (2021/01/18)
Herein, a light-driven, atom-economical process that provides access to enantiomerically enriched substituted chiral 1-pyrroline derivatives is introduced. The strategy involves the distal functionalization of acyl heterocycles through a hydrogen-atom transfer (HAT) process and the use of tailor-made ketimines as reliable electrophilic partners. This transformation is translated into an enantiomerically controlled radical/polar cascade reaction in which water is produced as the sole by-product and stereoselectivity is dictated by coordination to a chiral-at-rhodium catalyst.
Photoenzymatic Hydrogenation of Heteroaromatic Olefins Using ‘Ene’-Reductases with Photoredox Catalysts
Biegasiewicz, Kyle F.,Black, Michael J.,Chung, Megan M.,Hyster, Todd K.,Meichan, Andrew J.,Nakano, Yuji,Sandoval, Braddock A.,Zhu, Tianyu
supporting information, p. 10484 - 10488 (2020/04/29)
Flavin-dependent ‘ene’-reductases (EREDs) are highly selective catalysts for the asymmetric reduction of activated alkenes. This function is, however, limited to enones, enoates, and nitroalkenes using the native hydride transfer mechanism. Here we demonstrate that EREDs can reduce vinyl pyridines when irradiated with visible light in the presence of a photoredox catalyst. Experimental evidence suggests the reaction proceeds via a radical mechanism where the vinyl pyridine is reduced to the corresponding neutral benzylic radical in solution. DFT calculations reveal this radical to be “dynamically stable”, suggesting it is sufficiently long-lived to diffuse into the enzyme active site for stereoselective hydrogen atom transfer. This reduction mechanism is distinct from the native one, highlighting the opportunity to expand the synthetic capabilities of existing enzyme platforms by exploiting new mechanistic models.
Selective Acylation of Aryl- A nd Heteroarylmagnesium Reagents with Esters in Continuous Flow
Heinz, Benjamin,Djukanovic, Dimitrije,Ganiek, Maximilian A.,Martin, Benjamin,Schenkel, Berthold,Knochel, Paul
supporting information, p. 493 - 496 (2020/01/31)
A selective acylation of readily accessible organomagnesium reagents with commercially available esters proceeds at convenient temperatures and short residence times in continuous flow. Flow conditions allow us to prevent premature collapse of the hemiacetal intermediates despite noncryogenic conditions, thus furnishing ketones in good yields. Throughout, the coordinating ability of the ester and/or Grignard was crucial for the reaction outcome. This was leveraged by the obtention of several bisaryl ketones using 2-hydroxy ester derivatives as substrates.
Site-selective c-h acylation of pyridinium derivatives by photoredox catalysis
Jung, Sungwoo,Lee, Hyeonyeong,Moon, Yonghoon,Jung, Hoi-Yun,Hong, Sungwoo
, p. 9891 - 9896 (2019/10/14)
A strategy for visible-light-induced site-selective C-H acylation of pyridinium salts was developed by employing N-methoxy-or N-aminopyridinium salts, offering a powerful synthetic tool for accessing highly valuable C2- A nd C4-acylated pyridines. The met
Manganese-Catalyzed α-Alkylation of Ketones, Esters, and Amides Using Alcohols
Chakraborty, Subrata,Daw, Prosenjit,Ben David, Yehoshoa,Milstein, David
, p. 10300 - 10305 (2018/10/20)
Herein we report the manganese-catalyzed C-C bond-forming reactions via α-alkylation of ketones, amides, and esters, using primary alcohols. β-Alkylation of secondary alcohols by primary alcohols to obtain α-alkylated ketones is also reported. The reactions are catalyzed by a (iPr-PNP)Mn(H)(CO)2 pincer complex under mild conditions in the presence of (catalytic) base liberating water (and H2 in the case of secondary alcohol alkylation) as the sole byproduct.
Direct oxidation of the Csp3–H bonds of N-heterocyclic compounds to give the corresponding ketones using a reusable heterogeneous MnOx-N@C catalyst
Ren, Lanhui,Wang, Lianyue,Lü, Ying,Li, Guosong,Gao, Shuang
, p. 1216 - 1221 (2016/09/07)
Novel reusable MnOx-N@C catalyst has been developed for the direct oxidation of N-heterocycles under solvent-free conditions using TBHP as benign oxidant to give the corresponding N-heterocyclic ketones. The catalytic system exhibited a broad substrate scope and excellent regioselectivity, as well as being amenable to gram-scale synthesis. This MnOx-N@C catalyst also showed good reusability and was successfully recycled six times without any significant loss of activity.
A Nitrogen-Assisted One-Pot Heteroaryl Ketone Synthesis from Carboxylic Acids and Heteroaryl Halides
Demkiw, Krystyna,Araki, Hirofumi,Elliott, Eric L.,Franklin, Christopher L.,Fukuzumi, Yoonjoo,Hicks, Frederick,Hosoi, Kazushi,Hukui, Tadashi,Ishimaru, Yoichiro,O'Brien, Erin,Omori, Yoshimasa,Mineno, Masahiro,Mizufune, Hideya,Sawada, Naotaka,Sawai, Yasuhiro,Zhu, Lei
, p. 3447 - 3456 (2016/05/19)
A practical and highly effective one-pot synthesis of versatile heteroaryl ketones directly from carboxylic acids and heteroaryl halides under mild conditions is reported. This method does not require derivatization of carboxylic acids (preparation of acid chlorides, Weinreb amides, etc.) or the use of any additives/catalysts. A wide substrate scope of carboxylic acids with high functional group tolerance has also been demonstrated. The results reveal that the presence of an α-nitrogen on the halide substrate greatly improves the desired ketone formation.
N-heterocyclic carbene-catalyzed α-alkylation of ketones with primary alcohols
Zhu, Yanfang,Cai, Chun,Lu, Guoping
, p. 1666 - 1671 (2015/01/09)
Several N-heterocyclic carbene precursors are synthesized and used in the α-alkylations of ketones with primary alcohols. With the assistance of a base, these N-heterocyclic carbenes can catalyze the reaction smoothly to furnish dialkylated ketones in good-to-excellent yields.
Cyclodehydrations leading to indene products having n-heterocyclic substituents
Boblak, Kenneth N.,Klumpp, Douglas A.
, p. 5852 - 5857 (2014/07/08)
In this Note, we describe superacid-promoted cyclodehydrations leading to functionalized indenes. The product indenes are synthesized having N-heterocyclic substituents, including pyridyl, imidazolyl, pyrimdyl, and other groups. A mechanism is proposed in
