Suzuki–Miyaura cross-coupling coupling reactions with low catalyst loading: a green and sustainable protocol in pure water

Abstract

The Suzuki-Miyaura coupling reaction represents one of the most important synthetic transformations developed in the 20th century. However, the use of toxic organic solvents remains a scientific challenge and an aspect of economical and ecological relevance, and benign water as a reaction medium was found to be highly effective to overcome some of these issues. In the present manuscript, we described Suzuki-Miyaura coupling reactions in neat water, without using any phase transfer reagent. Notably, this protocol also works with ultra-low loading of catalyst with high turnover numbers and also able to couple challenging substrates like aryl chlorides.

The Arrangement of Two N-Heterocyclic Carbene Moieties in Palladium Pincer Complexes Affects Their Catalytic Activity towards Suzuki–Miyaura Cross-Coupling Reactions in Water

“…The reaction using 1.0 © 10 ¹3 mol % of the precatalyst C-N-C complex 2 afforded the product in 5% yield ( Table 1, Entry 5), whereas the reaction using the same quantity of C-C-N complex 1 gave the desired product in 75% yield with a turnover number (TON) value of 75,000 (Table 1, Entry 2). The TON value for 1 is relatively high but still lower than the reported values (770,000 14 and 800,000 6b ) for similar reactions in water. A smaller amount of 1 (1.0 © 10 ¹4 mol %) caused the yield to drop to 6% (Table 1, Entry 3).…”

Properties of the indole ring in metal complexes. A comparison with the phenol ring

“…Reactive solvated complexes may be formed in the course of organic reactions using Pd catalysts, such as some cross-coupling reactions of organic molecules. Recently it has been reported that decreasing the amount of the Pd-catalyst considerably enhanced the turnover numbers of cross-coupling reactions and that reactions at a higher concentration of the catalyst gave lower yields as seen in the catalyst concentration dependent cross-coupling reactions [64,65], where the proposed solvated complex intermediate may be also involved.…”

“…Metal-indole reaction intermediates may become important especially in the field of organic chemistry [64][65][66], and some biological compounds and drugs, such as tryptophan tryptophylquinone [67] and an anti-inflammatory agent indomethacin [68], have the indole moiety as an essential component. Useful C-C bond formation reactions have been developed by using metal complexes, especially Pd complexes.…”

Palladium-Catalyzed Coupling Reactions for the Functionalization of Si Surfaces: Superior Stability of Alkenyl Monolayers

“…10 -4 mol% Pd, 40 after Suzuki coupling. Both C 1s spectra display a peak at a binding energy of 288.6 eV, which is not present before coupling (Supporting Information, Figure S1) and can be assigned to the presence of an aromatic fluoride group (=C-F) 45 .…”