Palladium‐Catalyzed Decarboxylative Coupling of α‐ Oxocarboxylic Acids with C(sp²)H of 2‐Aryloxypyridines

Abstract

An efficient palladium-catalyzed decarboxylative ortho-acylation of 2-aryloxypyridines with a-oxocarboxylic acids is described. In this new transformation, the aromatic CA C H T U N G T R E N N U N G (sp 2 ) À H bond was successfully acylated to give diverse aromatic ketones regioselectively in moderate to good yields. The pyridine group can be removed easily after the acylation to give the corresponding 2-hydroxy aromatic ketones.

Supported Palladium Nanoparticles Catalyzed Ortho-Directed C–C Coupling Reaction via a Pd0/PdII/PdIV Catalytic Cycle

“…[7][8][9][10][11][12][13][14][15][16][17][18][19][20] The transition-metal-catalyzed direct aroylation of arenes bearing different directing groups (such as arylpyridines, benzamides, 2 acetophenone oximes and anilides) C-H bond represents a direct and promising approach to access ketones. [21][22][23][24][25][26][27][28][29][30][31] Many successful strategies involve Pd-catalyzed ortho-coupling reactions with C-H bonds through cyclopalladation of 2-phenylpyridine. [32][33][34][35][36][37][38][39][40][41][42][43][44] In 2009, Cheng 21 and Li 44 have reported Pd(OAc) 2 catalyzed synthesis of aromatic ketones using aromatic aldehydes as acyl sources via directed aromatic C-H bond activation.…”

Application of sugar-containing biomass: one-step synthesis of 2-furylglyoxylic acid and its derivatives from a vitamin C precursor

“…As a furan derivative, 2FGA is a precursor of the broad-spectrum antibiotic cefuroxime, 34–37 with a yield of approximately 40–90%. 38–40 Unfortunately, the production of 2FGA is limited, owing to its adverse properties (which are primarily caused by complex production steps, including cyanation, hydrolysis, and oximation) and the large amount of material consumption involved, resulting in serious carbon emissions and costly production.…”

Palladium‐Catalyzed Direct Acylation of Ketoximes and Aldoximes from the Alcohol Oxidation Level through C–H Bond Activation

“…Later, palladium‐ or rhodium‐catalyzed sp 2 C–H bond acylations of 2‐arylpyridines,10 oximes,11 amides,12 acetanilides,13 indoles,14 azobenzenes,15 and benzothiazoles16 with aldehydes were reported. Decarboxylative acylations of acetanilides,17 arylpyridines,18 phenoxypyridine,19 indole,20 enamides,21 oximes,22 amides,23 and carbamates24 using α‐keto acids as acyl equivalents have also been demonstrated. Recently, a palladium‐catalyzed acylation through C–C, C–H and C–O bond cleavage of α‐diketones, toluenes and carboxylic acids, respectively, was reported 25.…”