5798-79-8Relevant articles and documents
Reactivity of substrates with multiple competitive reactive sites toward NBS under neat reaction conditions promoted by visible light
Grjol, Bla?,Jereb, Marjan
, p. 5235 - 5248 (2021/06/07)
Regioselectivity of visible-light-induced transformations of a range of (hetero)aryl alkyl-substituted ketones bearing several competitive reactive sites (α-carbonyl, benzyl and aromatic ring) with N-bromosuccinimide (NBS) was studied under solvent-free reaction conditions (SFRC) and in the absence of inert-gas atmosphere, radical initiators and catalysts. An 8-W energy-saving household lamp was used for irradiation. Heterogeneous reaction conditions were dealt with throughout the study. All substrates were mono- or dibrominated at the α-carbonyl position, and additionally, some benzylic or aromatic bromination was observed in substrates with benzylic carbon atoms or electron-donating methoxy groups, respectively. Surprisingly, ipso-substitution of the acyl group with a bromine atom took place with (4-methoxynaphthyl) alkyl ketones. While the addition of the radical scavenger TEMPO (2,2,6,6-tetramethylpiperidin-1-yloxy) decreased the extent of α- and ring bromination, it completely suppressed the benzylic bromination and α,α-dibromination with NBS under SFRC.
Access to β-Ketonitriles through Nickel-Catalyzed Carbonylative Coupling of α-Bromonitriles with Alkylzinc Reagents
Donslund, Aske S.,Neumann, Karoline T.,Corneliussen, Nicklas P.,Grove, Ebbe K.,Herbstritt, Domenique,Daasbjerg, Kim,Skrydstrup, Troels
supporting information, p. 9856 - 9860 (2019/07/09)
Herein, we report a nickel-catalyzed carbonylative coupling of α-bromonitriles and alkylzinc reagents with near stoichiometric carbon monoxide to give β-ketonitriles in good yields. The reaction is catalyzed by a readily available and stable nickel(II) pincer complex. The developed protocol tolerates substrates bearing a variety of functional groups, which would be problematic or incompatible with previous synthetic methods. Additionally, we demonstrate the suitability of the method for carbon isotope labeling by the synthesis of 13C-labeled β-ketonitriles and their transformation into isotopically labeled heterocycles.
Palladium-Catalyzed, ortho-Selective C-H Halogenation of Benzyl Nitriles, Aryl Weinreb Amides, and Anilides
Das, Riki,Kapur, Manmohan
, p. 1114 - 1126 (2018/06/18)
A palladium-catalyzed, ortho-selective C-H halogenation methodology is reported herein. The highlight of the work is the highly selective C(sp2)-H functionalization of benzyl nitriles in the presence of activated C(sp3)-H bond, which results in good yields of the halogenated products with excellent regioselectivity. Along with benzyl nitriles, aryl Weinreb amides and anilides have been evaluated for the transformation using aprotic conditions. Mechanistic studies yield interesting aspects with respect to the pathway of the reaction and the directing group abilities.
