Stille cross‐coupling reaction using Pd/BaSO₄ as catalyst reservoir

Abstract

Stille cross-coupling reactions between iodobenzene and tributylphenyltin were carried out in ethanol/water solution using different amounts of Pd/BaSO 4 as catalyst reservoir in a ligand-free system and high yields were obtained. Other substituted biaryls were obtained with good yields. The catalyst can be reused up to three times with some loss in activity. Filtration of the catalyst and product extraction yielded a solution that kept its activity, showing the presence of Pd(0)/Pd(II) species that can be regarded as the true catalysts. Interestingly, both 2-bromotiophene and chlorobenzene yielded the desired corresponding reaction products.

A Facile Route to Bis(pyridyl‐1,3,5‐triazine) Ligands with Fluorescing Properties

“…ESI‐MS further validates the suggested structure with a distinctive chlorine isotope pattern at 270.11 and 272.11 m / z . Due to the lability of Cl‐dpt in basic conditions typically employed for Suzuki‐coupling reactions,22 the Stille coupling was performed under neutral conditions 23. With this synthetic procedure in hand, we were able to prepare the following dpt‐based ligands (see Scheme ).…”

Methodologies Limiting or Avoiding Contamination by Organotin Residues in Organic Synthesis

“…Finally, it is worth noting that the Stille cross-coupling reaction of phenyltributyltin using Pd/CaCO 3 or Pd/BaSO 4 was also reported in a mixture of ethanol and water.…”

Heck arylation of alkenes with aryl bromides by using supported Pd catalysts: a comparative study

“…When NMP was used as Reaction conditions: bromobenzene (4 mmol), styrene (4.8 mmol), NaOAc (5.8 mmol), additive (1 mmol), catalyst (0.1 mol% Pd), solvent (5 ml) T = 423 K, t = 3 h a Determined by GC-FID analysis b Selectivity of trans-stilbene a solvent, Pd/BaSO 4 was found to be the most active catalyst in the second catalytic cycle (Fig. 5), similarly to those observed for the Stille and Suzuki couplings [23,24]. However, in the third cycle, its activity was strongly decreased (the conversion was 29 %).…”

“…The catalysts used were as follows: Pd/C [17,[19][20][21] one of the most widely used heterogeneous Pd catalysts in Heck reactions; Pd/BaSO 4 [22][23][24], which has been shown to act as a catalyst reservoir in Stille and Suzuki-Miyaura couplings, but rarely used in Heck arylations, and Pd EnCat 30 [25][26][27][28][29][30], a commercial Pd(OAc) 2 catalyst, obtained by microencapsulation of palladiumacetate in polyurea matrix, formed by the condensation of multi-functional oligoarylisocyanates [31][32][33][34][35]. The properties of Pd EnCat were reported by the manufacturer, where only low leaching of Pd was detected [36].…”