Herrmann's catalyst

{{short description|Organopalladium compound used as a catalyst}}

{{Chembox

|ImageFile = HerrmannCat.png

|Section1={{Chembox Identifiers

|CASNo = 172418-32-5

|PubChem = 15978061

|UNII = 0K4FY6KS4N

|ChemSpiderID = 10136140}}

|Section2={{Chembox Properties

|C=46|H=46|O=4|P=2|Pd=2

|Appearance = Yellow solid

|MeltingPtC = 123-125

}}

}}

Herrmann's catalyst is an organopalladium compound that is a popular catalyst for the Heck reaction. It is a yellow air-stable solid that is soluble in organic solvents. Under conditions for catalysis, the acetate group is lost and the Pd-C bond undergoes protonolysis, giving rise to a source of "{{chem2|PdP(o\-tol)3}}".

The complex is made by reaction of tris(o-tolyl)phosphine with palladium(II) acetate:{{cite journal|author=Herrmann, W. A.|author2=Brossmer, C.|author3=Reisinger, C.-P.|author4=Riermeier, T. H.|author5=Öfele, K.|author6=Beller, M.|title=Palladacycles: Efficient New Catalysts for the Heck Vinylation of Aryl Halides|journal=Chemistry – A European Journal|year=1997|volume=3|pages= 1357–1364|doi=10.1002/chem.19970030823}}

:{{chem2 | 2 Pd(OAc)2 + 2 P(o\stolyl)3 -> 2 HOAc + Pd2(OAc)2[P(o\stolyl)(o\stolyl)2]2 }}

Many analogues of Hermann's catalyst have been developed, e.g. palladacycles obtained from 2-aminobiphenyl.{{cite journal|author=Bruneau, A.|author2= Roche, M.|author3= Alami, M.|author4=Messaoudi, S.|title=2-Aminobiphenyl Palladacycles: The "Most Powerful" Precatalysts in C–C and C–Heteroatom Cross-Couplings|journal=ACS Catalysis|year=2015|volume=5|pages=1386–1396|doi=10.1021/cs502011x}}