The Open Organic Chemistry Journal

2008, 2 : 1-9
Published online 2008 March 10. DOI: 10.2174/1874095200801020001
Publisher ID: TOOCJ-2-1

Steric and Electronic Effects of Benzoferrocenyl Phosphine Ligands on Palladium-Catalyzed Allylic Alkylation and Suzuki Coupling Reactions

Muralidhara Thimmaiah , Rudy L. Luck and Shiyue Fang
Department of Chemistry, Michigan Technological University, 1400 Townsend Drive, Houghton, MI 49931, USA.

ABSTRACT

Five benzoferrocenyl phosphine ligands with the phosphorus atom attached to the 5-position of the benzoferrocene and some ligand-Mo(CO)5 complexes were prepared and fully characterized; the structure of one ligand was confirmed by X-ray crystallography. These ligands were applied in palladium-catalyzed allylic alkylation and Suzuki coupling of chlorobenzene with phenylboronic acid. Results were compared with those reported previously using ligands having the phosphorus atom attached to the 4-position of benzoferrocene. This structural modification resulted in an increase of activity of the ligands in allylic alkylation reaction but a decrease of activity in Suzuki coupling reactions. The underlying reasons are analyzed with the help of X-ray single crystal determined structures and CO stretching frequencies in the IR spectra of complexes between the ligands and Mo(CO)5.

Keywords:

Benzoferrocene, Suzuki coupling, Allylic alkylation.