7469-80-9Relevant articles and documents
From Esters to Ketones via a Photoredox-Assisted Reductive Acyl Cross-Coupling Strategy
Chen, Yukun,Li, Weirong,Luo, Yixin,Qi, Xiaotian,Xi, Xiaoxiang,Xu, Minghao,Yuan, Weiming,Zhao, Hongping,Zheng, Songlin
supporting information, (2021/12/06)
A method was developed for ketone synthesis via a photoredox-assisted reductive acyl cross-coupling (PARAC) using a nickel/photoredox dual-catalyzed cross-electrophile coupling of two different carboxylic acid esters. A variety of aryl, 1°, 2°, 3°-alkyl 2-pyridyl esters can act as acyl electrophiles while N-(acyloxy)phthalimides (NHPI esters) act as 1°, 2°, 3°-radical precursors. Our PARAC strategy provides an alternative and reliable way to synthesize various sterically congested 3°-3°, 3°-2°, and aryl-3° ketones under mild and highly unified conditions, which have been otherwise difficult to access. The combined experimental and computational studies identified a Ni0/NiI/NiIII pathway for ketone formation.
Palladium-NHC (NHC = N-heterocyclic Carbene)-Catalyzed Suzuki-Miyaura Cross-Coupling of Alkyl Amides
Wang, Chang-An,Rahman, Md. Mahbubur,Bisz, Elwira,Dziuk, B?az?ej,Szostak, Roman,Szostak, Michal
, p. 2426 - 2433 (2022/02/17)
We report the Pd-catalyzed Suzuki-Miyaura cross-coupling of aliphatic amides. Although tremendous advances have been made in the cross-coupling of aromatic amides, C-C bond formation from aliphatic amides by selective N-C(O) cleavage has remained a major challenge. This longstanding problem in Pd catalysis has been addressed herein by a combination of (1) the discovery of N,N-pym/Boc amides as a class of readily accessible amide-based reagents for cross-coupling and (2) steric tuning of well-defined Pd(II)-NHC catalysts for cross-coupling. The methodology is effective for the cross-coupling of an array of 3°, 2°, and 1° aliphatic amide derivatives. The catalyst system is user-friendly, since the catalysts are readily available and are air- and bench-stable. Mechanistic studies strongly support an amide bond twist and external nN → π*C═O/Ar delocalization as a unified enabling feature of N,N-pym/Boc amides in selective N-C(O) bond activation. The method provides a rare example of Pd-NHC-catalyzed cross-coupling of aliphatic acyl amide electrophiles.
Nickel-Mediated Photoreductive Cross Coupling of Carboxylic Acid Derivatives for Ketone Synthesis**
Brauer, Jan,Quraishi, Elisabeth,Kammer, Lisa Marie,Opatz, Till
supporting information, p. 18168 - 18174 (2021/11/30)
A simple visible light photochemical, nickel-catalyzed synthesis of ketones from carboxylic acid-derived precursors is presented. Hantzsch ester (HE) functions as a cheap, green and strong photoreductant to facilitate radical generation and also engages in the Ni-catalytic cycle to restore the reactive species. With this dual role, HE allows for the coupling of a large variety of radicals (1°,2°, benzylic, α-oxy & α-amino) with aroyl and alkanoyl moieties, a new feature in reactions of this type. With both precursors deriving from abundant carboxylic acids, this protocol is a welcome addition to the organic chemistry toolbox. The reaction proceeds under mild conditions without the need for toxic metal reagents or bases and shows a wide scope, including pharmaceuticals and complex molecular architectures.
