Nickel-Catalyzed Hiyama-type Decarboxylative Coupling of Propiolic Acids and Organosilanes

Abstract

A Ni catalytic system was developed for the decarboxylative coupling reaction of alkynyl carboxylic acids with organosilanes. Ni(acac)2 and 1,10-phenanthroline showed the best result in the presence of CsF and CuF2 at 120 °C. This system tolerated the presence of alkyl, alkoxy, halogen, nitro, cyano, ketone, and ester functional groups. Moreover, the reaction with but-2-ynedioic acid and organosilane afforded the corresponding symmetrical diarylalkynes.

Introducing Trifluoromethoxyarenes as Halide Surrogates in Mechanochemical Realizations of Ni‐catalyzed Cross‐coupling Reactions

“…[29][30][31] In this case as well, the authors suggest an important role of the CsF as silane activator forming an anionic SiÀ F complex that enters the transmetalation step. [29,30] Finally, further extending the pool of reaction partners, we turned our attention to potassium benzoyltrifluoroborates. Potassium acyltrifluoroborates (KATs) are an emerging class of intermediates with very interesting reactivities, yet to be fully explored.…”

“…Aryl trifluoroborates are perceived as “protected boronic acids”, for it was evidenced that aryl difluorohydroxyborate intermediates are the actual organoboron species entering the coupling process (transmetalation step) [28] . As a further extension of the current investigations, we also applied aryl trialkoxysilanes as reaction partners, realizing a Hiyama‐type cross‐coupling (Scheme 1l) that has been investigated previously also in Ni‐catalyzed scenarios, however to date, no examples in combination with aryl ethers were presented [29–31] . In this case as well, the authors suggest an important role of the CsF as silane activator forming an anionic Si−F complex that enters the transmetalation step [29,30] …”

Transition Metal Catalyzed Hiyama Cross-Coupling: Recent Methodology Developments and Synthetic Applications

“…The symmetrical diarylacetylenes were synthesized in a 21–45% yield range under optimized reaction conditions. It was noticed that variation in reaction conditions (in the presence of TEMPO and the absence of CuF 2 , CsF, and Ni ligands) resulted in relatively low yields of corresponding products [ 198 ].…”

An Efficient and Sustainable Approach to Decarboxylative Cross-Coupling Using Silica Coated Magnetic Copper Nanocatalyst for the Synthesis of Internal Alkynes

“…To date, a number of homogeneous catalytic systems using palladium, copper and nickel catalysts have been developed for the decarboxylative coupling of alkynoic acids with haloarenes. ( Edwin Raja et al, 2016 ). However, most of them employ toxic phosphine ligands, and costly additives that are also air and moisture sensitive.…”