The potential of Pd/Pt complexes for catalytic carboxylation of arenes with CO2 is investigated by means of computational chemistry. Recently we reported that the bis[(2‐methoxyphenyl)phosphino]‐benzenesulfonamido palladium complex 1 inserts CO2 reversibly in its Pd−C(aryl) bond generating carboxylato complex 2. In the present work we study how geometric and electronic factors of various ligands and substrates influence the overall activation barrier (energy span, ES) of a potential catalytic cycle for arene carboxylation comprising this elementary step. The tendency of the key intermediates to dimerize and thus deactivating the potential catalysts is examined as well as the role of the base, which inevitably is needed to stabilize the reaction product. We show that Pd and Pt complexes I(Pd)‐L16‐S1 and I(Pt)‐L16‐S1 do not dimerize, enable the computation of complete catalytic cycles, and show interestingly low ES values of 26.8 and 24.5 kcal/mol, respectively.

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.

A highly chemo-and regioselective decarboxylative Heck-type coupling of carboxylic acids and terminal olefins has been developed using a catalytic system composed of Pd(OAc) 2 in the presence of phosphine-sulfonamido ligands. Using the bulky ligand L1 leads to high selectivity for 1,1-disubstituted (branched; b) olefins that are generally difficult to obtain. The influence of all relevant reaction parameters was evaluated using a combination of design of experiments and one factor at a time optimization. The coupling of dimethoxy-benzoic acid with various olefinic substrates gave the corresponding branched olefins with excellent regioselectivity (b/l up to 42:1) in up to 80% isolated yields. In contrast, using the less bulky ligand L2 results in the inverse regioselectivity leading to the 1,2-disubstituted (linear; l) product again in high yield of 86% (b/l = 1:26). Detailed investigation of the mechanistic pathways by DFT calculations reveals that the sterically demanding aryl substituent at the sulfonamide group of ligand L1 favors the pathway via 1,2-insertion with an energy preference of 4.4 kcal/mol, thus furnishing the 1,1-disubstituted branched olefins. In contrast, the 2,1-insertion reaction is advantageous by 1.3 kcal/mol for the analogous less bulky ligand L2 leading to the linear products.