Palladium‐Catalyzed Carbonylations of Arylboronic Acids: Synthesis of Arylcarboxylic Acid Ethyl Esters

Abstract

An approach for the palladium-catalyzed ethoxycarbonylations of arylboronic acids using diethyl pyrocarbonate as carbon monoxide/carbon dioxide (CO/CO 2 )s urrogate in moderate to good yields has been investigated.

Na4PMo11VO40-catalyzed one-pot oxidative esterification of benzaldehyde with hydrogen peroxide

“…The selectivity was calculated from eqn (2), where the corrected area of the GC peak of each product (A p ) was compared to the initial area of the GC peak of benzaldehyde (A 0 )eqn (2)…”

“…1 However, the traditional routes of ester production involve hazardous and environmentally unfriendly reagents, which leads to large generation of stoichiometric quantities of residues and effluents. 2 To circumvent these drawbacks, alternative routes to the traditional stoichiometric oxidation processes, such as the direct transformation in one-pot reactions of aldehydes into esters, have been developed. 3 Indeed, the oxidative esterication of aldehydes has been raised as a sustainable and efficient alternative to classical synthesis.…”

“… 1 However, the traditional routes of ester production involve hazardous and environmentally unfriendly reagents, which leads to large generation of stoichiometric quantities of residues and effluents. 2 …”

Rhodium‐Catalyzed Additive‐Free C−H Ethoxycarbonylation of (Hetero)Arenes with Diethyl Dicarbonate as a CO Surrogate

“…To address this issue, we focused on metal alkoxide species, which can be generated in situ from a transition metal catalyst and a dicarbonate, as an alternative source of the external base. Oxidative addition of dicarbonates to transition metals is known to produce metal alkoxide species along with CO 2 , [18] and the metal alkoxide species should activate a CÀ H bond if an appropriate transition metal catalyst is selected. Herein, we report the rhodium-catalyzed CÀ H ethoxycarbonylation of arenes using diethyl dicarbonate in the absence of additives (Scheme 1c).…”

“…[19] 1-(Pyrimidin-2-yl)-1H-indole (1 a) was chosen as a model substrate for this transformation, and various transition metal salts were initially tested in the presence of diethyl dicarbonate (2). The palladium catalyst employed previously for the alkoxycarbonylation of arylboronic acids using decarbonates [18] was unsuccessful for the CÀ H alkoxycarbonylation of 1 a (entry 1). Other transition metal salts, such as those derived from iridium and ruthenium, [12] also failed to promote the reaction (entries 2 and 3).…”