On the Involvement of Palladium Nanoparticles in the Heck and Suzuki Reactions

Abstract

We describe two different pathways by which palladium-catalyzed Heck and Suzuki coupling reactions take place. When sol-gel entrapped palladium acetate was used as a catalyst, the reactions proceed by the formation of metallic nanoparticles. Such particles were already formed during the immobilization of the palladium salt. Upon application of palladium derivatives of proline, tyrosine, or alanine, either in their homogeneous or in their sol-gel entrapped version, no Pd 0 particles could be detected, even when the couplings were carried out in boiling mesitylene (161°C) or during pro-

Investigation of microwave‐assisted synthesis of palladium nanoparticles supported on Fe3O4 as efficient recyclable magnetic catalysts for Suzuki‐Miyaura cross‐coupling

“…The binding energy at 341.38 and 336.23 eV are ascribed to Pd 3d 3/2 and Pd 3d 5/2 , respectively, and this confirms that Pd was present as PdO (Pd 2+ ). This is in agreement with other reported data showing the role of the addition of Fe on the activity of the Pd‐containing catalysts …”

Catalytic transfer hydrogenation of hydrophobic substrates by water-insoluble hydrogen donors in aqueous microemulsions

“…However, now we have found that during the transfer hydrogenation of 1-chloromethylnaphthalene (Scheme 6a) that undergoes easy hydrolysis (Scheme 6b), part of the substrate reacts with the aqueous medium to form 1-naphthalenemethanol (Table 2, entries [13][14][15].…”

“…Consequently, a short induction period is usually observed in the initial stage of the first catalytic process. The metallic particles formed during the entrapment in the sol-gel matrix and those produced during the transfer hydrogenation in the first run differ in their sizes [13]. While the aggregates formed before the catalytic reaction are mostly between 40 and 50 nm, the diameters of the particles that are added during the transfer hydrogenation [of (Z)-stilbene] are of the order of 5-8 nm (see Fig.…”

Facile Microwave-Assisted Synthetic Approach to Palladium Nanoparticles Supported on Copper Oxide as an Efficient Catalyst for Heck and Sonogashira Cross-Coupling Reactions

“…Cross-coupling reactions, such as Heck and Sonogashira reactions play a crucial role in pharmaceutical and organic synthesis. 13,14 The possibility of using microwave heating for various reactions using nanocatalysis is a convenient synthetic route to green chemistry. 15 Many reactions such as cross-coupling reactions used for C-C bond formation are now relevant processes in chemical transformations and can be applied in many scienti¯c areas including pharmacy, natural products, agriculture and cosmetics.…”