Palladium‐Catalyzed Regioselective Aerobic Oxidative CH/NH Carbonylation of Heteroarenes under Base‐Free Conditions

Abstract

Transition-metal-catalyzed alkoxycarbonylation reactions usually involve aryl halide ArX as the electrophile and CO/ ROH as the nucleophile (Scheme 1, Path 1). As an alternative avenue, the oxidative carbonylation between an aryl metal ArM and CO/ROH by employing stoichiometric amount of oxidants has recently attracted increasing attention (Scheme 1, Path 3). Apparently, if simple arenes ArH were directly employed as the nucleophile and air or O 2 as the terminal oxidant in oxidative carbonylation, this challenging transformation will present an attractive and sustainable approach towards the synthesis of carbonyl compounds (Scheme 1, Path 2).Carboxylic acids and derivatives (e.g., esters) are valuable commodity chemicals and useful synthetic building blocks for agrochemicals, active pharmaceutical ingredients and process chemicals. Since the pioneering work of Heck and co-workers in 1974, [1] transition-metal-catalyzed carbonylation reactions of aromatic halides ArX in the presence of CO and ROH affording ArCO 2 R have undergone rapid development and been widely applied in industry in the last several decades, [2] whereas ArX is usually prepared from the corresponding ArH and a stoichiometric amount of bases is required to facilitate the reaction.

Accessing the HMF Derivatives from Furfural Acetate through Oxidative Carbonylation

“…Surprisingly, increasing the catalyst loading resulted in a dramatic decrease of catalytic activity, and reducing the amount of furfuryl acetate substrate also led to the yield to decrease (Table , entries 10 and 11). The intrinsic origins for these phenomena were still unclear, and similar phenomenon was even observed in carbonylation of indoles and thiophenes reported in the literature . Even though, the achieved 49.6% yield of carbonylation product with 54.4% of conversion in present studies has been the highest one in all of the reported systems for furan frame .…”

Preparation and photocatalytic activity of fluoroalkyl end-capped vinyltrimethoxysilane oligomer/anatase titanium oxide nanocomposite-encapsulated low molecular weight aromatic compounds

“…This finding would be due to the effective oleophilic-oleophilic interaction between the aromatic compounds in the fluorinated nanocomposites and MB. It was hitherto reported that fluorine-doped TiO 2 nanoparticles can enhance the photocatalytic activity, compared with that of the original one, due to the formation of Ti-F species on the facets, especially surface terminating Ti-F bonds in the surface Ti-O-Ti networks [20, [34][35][36][37][38][39][40][41][42]. Therefore, it is expected that the higher photocatalytic activity related to R F -(VM-SiO 2 ) n -R F /anTiO 2 /Ar-H nanocomposites even after calcination at Table 1 (or original anTiO 2 nanoparticles) before and after calcination at 1,000°C.…”

Palladium‐Catalyzed Aerobic Oxidative Carbonylation of C–H Bonds in Phenols for the Synthesis of p‐Hydroxybenzoates

“…However, most progress has been achieved with compounds containing directing groups and with the use of hazardous metals and oxidants such as copper, silver salts or peroxides, which are undesirable from a green chemistry point of view. Molecular oxygen is an ideal and readily available, nonhazardous oxidant for oxidative carbonylation …”