Home
Resources
Publications
Cavity-shaped Ligands: calix[4]arene-based Monophosphanes for Fast Suzuki-Miyaura Cross-Coupling

Cavity-shaped Ligands: calix[4]arene-based Monophosphanes for Fast Suzuki-Miyaura Cross-Coupling

Laure Monnereau, David Sémeril, Dominique Matt, Loïc Toupet

Chemistry. 2010 Aug 9;16(30):9237-47.

PMID: 20583042

Abstract:

Five conical calix[4]arenes that have a PPh(2) group as the sole functional group anchored at their upper rim were assessed in palladium-catalysed cross-coupling reactions of phenylboronic acid with aryl halides (dioxane, 100 degrees C, NaH). With arylbromides, remarkably high activities were obtained with the catalytic systems remaining stable for several days. The performance of the ligands is comparable to a Buchwald-type triarylphosphane, namely, (2'-methyl[1,1'-biphenyl]-2-yl)diphenylphosphane, which in contrast to the calixarenyl phosphanes tested may display chelating behaviour in solution. With the fastest ligand, 5-diphenylphosphanyl-25,26,27,28-tetra(p-methoxy)benzyloxy-calix[4]arene (8), the reaction turnover frequency for the arylation of 4-bromotoluene was 321,000 versus 214,000 mol(ArBr).mol(Pd)(-1).h(-1) for the reference ligand. The calixarene ligands were also efficient in Suzuki cross-coupling reactions with aryl chlorides. Thus, by using 1 mol% of [Pd(OAc)(2)] associated with one of the phosphanes, full conversion of the deactivated arenes 4-chloroanisole and 4-chlorotoluene was observed after 16 h. The high performance of the calixarenyl-phosphanes in Suzuki-Miyaura coupling of aryl bromides possibly relies on their ability to stabilise a monoligand [Pd(0)L(ArBr)] species through supramolecular binding of the Pd-bound arene inside the calixarene cavity.

Chemicals Related in the Paper:

Catalog Number	Product Name	Structure	CAS Number	Price
AP146631007	4-(Benzyloxy)phenylboronic acid		146631-00-7	Price
AP190661291	2-(Benzyloxy)phenylboronic acid		190661-29-1	Price

As a specialist in analytical chemical Products, Alfa Chemistry offers consumers a wealth of raw materials and a full range of technologies and services.

QUICK LINKS

HEADQUARTERS

Tel:

Fax:

Email: