Reaction monitoring reveals poisoning mechanism of Pd2(dba)3 and guides catalyst selection.

Title Reaction monitoring reveals poisoning mechanism of Pd2(dba)3 and guides catalyst selection.
Authors Colletto, C.; Burés, J.; Larrosa, I.
Journal Chem Commun (Camb)
DOI 10.1039/c7cc08018b
Abstract

We have discovered that the dba ligand in the commonly used Pd(dba)·CHCl cross-coupling pre-catalyst is susceptible to bis-arylation when used in the presence of aryl iodides. The in situ formed dbaAr ligands result in Pd-species with altered catalytic activity. In the case of study, the room temperature C3 arylation of benzo[b]thiophenes with aryl iodides, we have observed a marked catalyst deactivation when dba is arylated with electron-deficient aryl iodides, accounting for the poor yields obtained in the C3 arylation reactions with these aryl iodides. Based on these studies, we report a new catalytic system, employing a dba-free Pd catalyst, which allows for the first time the direct C3 arylation of benzo[b]thiophenes with electron-deficient aryl iodides at room temperature.

Citation Colletto, C.; Burés, J.; Larrosa, I..Reaction monitoring reveals poisoning mechanism of Pd2(dba)3 and guides catalyst selection..

Related Elements

Palladium

46 Pd 106.420000000 Palladium

Palladium Bohr ModelSee more Palladium products. Palladium (atomic symbol: Pd, atomic number: 46) is a Block D, Group 10, Period 5 element with an atomic weight of 106.42. The number of electrons in each of palladium's shells is 2, 8, 18, 18 and its electron configuration is [Kr] 4d10. The palladium atom has a radius of 137 pm and a Van der Waals radius of 202 pm. In its elemental form, palladium has a silvery white appearance. Palladium is a member of the platinum group of metals (along with platinum, rhodium, ruthenium, iridium and osmium). Elemental PalladiumPalladium has the lowest melting point and is the least dense of the group. Palladium can be found as a free metal and alloyed with other platinum-group metals. Nickel-copper deposits are the main commercial source of palladium. Palladium was discovered and first isolated by William Hyde Wollaston in 1803. Its name is derived from the asteroid Pallas.

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