Heck–Matsuda Reactions Catalyzed by a Hydroxyalkyl‐Functionalized NHC and Palladium Acetate

Abstract

The functionalized NHC obtained from salt 2 is a good ligand for palladium in the Heck–Matsuda reaction of arenediazonium salts and different alkenes. The reaction is performed with low catalyst loading (0.5–1 mol‐% of Pd) and in the absence of a base for acrylates. The protocol is also useful for the preparation of cinnamide derivatives. Compound U‐77863 has been prepared successfully in good isolated yield. Cyclohexene was found to be an appropriate substrate for the reaction, giving the corresponding 1‐arylcyclohexene as a single regioisomer under the studied reaction conditions. The optimal parameters of the reaction were studied by employing a design of experiments approach. Thus, the use of a small set of reactions allows the trends of the different factors to be studied. This study revealed that the best catalytic system is formed by combination of Pd(OAc)2 and salt 2 in a 1:2 ratio. This catalytic system produces better results without the use of a base.

Palladium nanoparticles supported on agarose‐catalyzed Heck–Matsuda and Suzuki–Miyaura coupling reactions using aryl diazonium salts

“…Using aryl diazonium salts in Heck, Suzuki, Sonogashira and Hiyama reactions has attracted attention in recent years. The reactions can be performed in the presence of N ‐heterocyclic carbene ligands, palladacycle systems or under ligand‐free conditions . A Pd/charcoal catalytic system has been recently used as a heterogeneous catalyst in the Heck–Matsuda coupling reaction of aryl diazonium salts.…”

Enantioselective Heck–Matsuda Arylations through Chiral Anion Phase‐Transfer of Aryl Diazonium Salts

“…This hypothesis implies that the anion might be leveraged to mediate reactivity and selectivity arising from any or all of the elementary steps in the catalytic cycle . More specifically, alkene isomerization position by a palladium hydride intermediate ( 5 ), which has been previously noted as an issue of the Heck-Matsuda reaction of unactivated cyclic alkenes, [4b,13] might be subject to anion control. However, while the number of examples of chiral phosphate anion-controlled enantioselectivity is rapidly increasing, the use of these anions to influence reaction outcomes beyond enantioselectivity remains rare.…”

Substrate-Directed Heck–Matsuda Arylations

“…28 In the case of the Heck-Matsuda reaction, cycloalkenes have been used as substrates, but a complex mixture of the styrenil and allylic products is often observed (Scheme 23). 34 We realized that DGs could be attached to cyclopentenes to control the stereoselectivity of the process, thus allowing the syntheses of fully functionalized arylcyclopentenes. 34 We realized that DGs could be attached to cyclopentenes to control the stereoselectivity of the process, thus allowing the syntheses of fully functionalized arylcyclopentenes.…”