Pd(II)-catalyzed carboxylation of aromatic C─H bonds with CO ₂

Abstract

The carboxylation of nonactivated C─H bonds provides an attractive yet hitherto largely elusive chemical process to synthesize carboxylic acids by incorporation of CO 2 into the chemical value chain. Here, we report on the realization of such a reaction using simple and nonactivated arenes as starting materials. A computationally designed Pd(II) complex acts as organometallic single-component catalyst, and apart from a base, necessary for thermodynamic stabilization of the intermediates, no other additives or coreagents are required. Turnover numbers up to 10 2 and high regioselectivities are achieved. The potential of this catalytic reaction for “green chemistry” is demonstrated by the synthesis of veratric acid, an intermediate for pharmaceutical production, from CO 2 and veratrol.

Visible-light-driven photocatalytic carboxylation to aromatic carboxylic acids with CO2

“…63 A similar process was discovered for the traditional palladium-catalyzed carboxylation with CO 2 to prepare aromatic carboxylic acids. 64,65 Finally, D was reduced by one electron from Ir(II) to generate Pd(0), which then proceeded to the next catalytic cycle. Subsequently, aryl carboxylate which underwent further acidification resulted in the formation of aromatic carboxylic acids.…”

Computational design of cooperatively acting molecular catalyst systems: carbene based tungsten- or molybdenum-catalysts with rhodium- or iridium-complexes for the ionic hydrogenation of N2 to NH3

“…One must note, however, that it cannot be excluded completely, that unexpected side reactions may be accessible in an experimental system which might not have been envisioned or possibly overlooked in the prior computational work. Computational studies of this kind have demonstrated their potential to narrow down significantly the plethora of choices an experimentalist could make with the potential of predictive catalyst design for example for olefin hydrogenation, 16 decarboxylative Heck-type coupling 13 and direct insertion of CO 2 14,15 into arenes.…”

“…In this work we use computationally guided catalyst design for the identification of suitable catalyst systems which bases on DFT computations following an approach which has been used earlier by us and was successfully transferred to experimental chemistry. 13–16…”

Density Functional Theory Study of the Mechanism of Ni-Catalyzed Carboxylation of Aryl C(sp2)–S Bonds with CO2: Computational Evidence for the Multifaceted Role of Additive Zn

“…In 2023, Leitner’s group reported the use of a Pd II complex as an organometallic single-component catalyst for the simple and non-activated direct carboxylation of aromatic C–H bonds with CO 2 . The reaction requires no additives other than the base required to stabilize the intermediate product and turnover numbers of ≤10 2 , and high regioselectivities are achieved . However, due to the challenges of the inertness and selectivity of C–H bonds, the direct carboxylation of aryl C–H bonds with CO 2 still has defects such as a narrow substrate range, a large catalyst loading, and harsh reaction conditions .…”