A mixed NCP pincer palladacycle as catalyst precursor for the coupling of aryl halides with aryl boronic acids

Estratégias para estudo das correlações de energia livre em acoplamento aril-aril de Suzuki: elucidando ciclos catalíticos através da equação de Hammett

“…Essa pequena sensibilidade ao grupo substituinte justifica o sucesso da aplicação do ciclopaladato 1 no acoplamento dos diversos haletos de arila (Cl, Br e I). 4 Um belo trabalho de investigação sobre aspectos mecanísticos do acoplamento de Heck, promovido por ciclopaladatos, foi apresentado por Dupont. 11 Nele foi avaliada a influência do grupo substituinte em brometos de arila na reação com acrilato de n-butila através de quatro ciclopaladatos.…”

“…Os ácidos arilborônicos que não foram sintetizados no laboratório eram da marca Combi-blocks, Inc. O ciclopaladato do tipo pinça NCP 1 foi preparado de acordo com a literatura. 4 As análises de cromatografia gasosa foram realizadas em um cromatógrafo gasoso Hewlett-Packard-5890 com detector FID e uma…”

“…Tal precursor catalítico desenvolvido mostrou-se eficiente nesse acoplamento, sendo listado como um dos mais eficientes sistemas catalíticos que operam com paládio isento de fosfinas relatados até o momento. 4 …”

Facile synthesis of achiral and chiral PCN pincer palladium(II) complexes and their application in the Suzuki and copper-free Sonogashira cross-coupling reactions

“…To our knowledge, palladacycles including pincer palladacycles usually show high activities at 90-100°C or higher temperatures for Pd-catalyzed C-C coupling reactions since high temperature helps the cleavage of stable palladacycles [Pd(II)] to form the catalytically active Pd(0) species [21][22][23]. For example, Dupont's PCN pincer complex was quite efficient for the Suzuki coupling of both deactivated and activated aryl chlorides with a catalyst loading of 1 mol% at 130°C [39]. While the reaction of more reactive 4-bromoacetophenone with PhB(OH) 2 in the presence of 0.1 mol% of Uozumi's PCP-bis(phosphinite) pincer Pd complex at 110°C only gave a 60% yield after 24 h [23].…”

Synthesis and applications of a new palladacycle as a high active catalyst in the Suzuki couplings

“…Of note is that the best results were obtained with phosphapalladacycles or with palladacycles modified with carbenes or phosphorus containing ligands. This might be rationalized by the extra stability provided by these ligands for the stabilization of the low-ligated catalytically active Pd species involved in the main catalytic cycle [14,2,15]. Also Bedford and co-workers recently investigated the possibility of using related palladated triarylphosphite complexes and found extremely high activity in Suzuki cross coupling with both electronically activated and deactivated aryl bromides [16,17].…”