Pd(II)-Catalyzed Arylation/Oxidation of Benzylic C–H of 8-Methylquinolines: Access to 8-Benzoylquinolines

Abstract

An efficient access to 8-benzoylquinoline was developed by a sequential arylation/oxidation of 8-methylquinolines with aryl iodides in the presence of Pd­(OAc)2. This transformation demonstrates good tolerance of a wide range of functional groups on aryl iodides, providing good to excellent yields of 8-benzoylquinolines.

Palladium-catalyzed native α-amino acid derivative-directed arylation/oxidation of benzylic C–H bonds: synthesis of 5-aryl-1,4-benzodiazepin-2-ones

“…According to the results from previous studies 6–8 and our experimental results, a plausible reaction path is proposed (Scheme 4). First, coordination of the Pd( ii ) species with substrate 1 and subsequently the first benzylic C–H activation leads to the formation of intermediate A .…”

“…7 a In 2021, Li and co-workers developed a palladium-catalyzed arylation/oxidation of the benzylic C–H bond in 8-methylquinolines with aryl iodides. 7 b Inspired by these works, 7 we performed an arylation/oxidation reaction using a N -Tfac-protected valine derivative ( 1a ) as the test substrate. When this compound was reacted with iodobenzene ( 2a ) under Zhang's conditions, no desired products 3a was observed (Table 1, entry 1).…”

Palladium-Catalyzed Directed Aldehyde C–H Arylation of Quinoline-8-carbaldehydes: Exploring the Reactivity Differences between Aryl (Pseudo) Halides

“…Pd­(OAc) 2 -catalyzed sequential arylation/oxidation of 8-methylquinolines with aryl iodides to synthesize aryl quinolinyl ketones was reported by Li et al Although excellent methodologies were developed for the synthesis of 8-aryloylquinolines, in all of the cases expensive Rh catalyst or Ru/Pd dual catalyst was used, and the electronic nature of the substrate diverges the yield. In continuation of our work on C–H activation, herein, we report Pd-catalyzed aldehyde C–H bond activation and direct coupling of quinoline-8-carbaldehydes with two types of arylating agent, aryl iodide and aryl diazonium salts, to afford a variety of aryl quinolinyl ketones from readily available chemicals.…”

“… a Compounds illustrating the importance of 8-aryloylquinoline moiety. a Figure is reproduced from refs and .…”