title: Synthesis of bulky arylphosphanes by rhodium-catalyzed formal [2+2+2] cycloaddition reaction and their use as ligands.
abstract: Treatment of 1-alkynylphosphane sulfides with 1,6- or 1,7-diynes in the presence of a cationic rhodium catalyst results in a formal [2+2+2] cycloaddition reaction to afford the corresponding aromatic phosphane sulfides. The aromatic rings formed in the cycloaddition naturally bear one or two substituents at the ortho positions to the phosphorus atom, which creates a sterically hindered environment around the phosphorus atom. The following desulfidation of the products is facile under radical conditions or with the aid of tris(dimethylamino)phosphane, providing the corresponding bulky phosphanes. Dicyclohexyl(2,6-diphenylaryl)phosphane, which is available through this sequence, proves to serve as an efficient ligand in palladium-catalyzed cross-coupling amination reactions.
authors.affiliation: Department of Material Chemistry, Graduate School of Engineering, Kyoto University, Kyoto-daigaku Katsura, Nishikyo, Kyoto 615-8510, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Kobatake
authors.forename: Azusa
authors.initials: A
authors.lastname: Kondoh
authors.forename: Suguru
authors.initials: S
authors.lastname: Yoshida
authors.forename: Hideki
authors.initials: H
authors.lastname: Yorimitsu
authors.forename: Koichiro
authors.initials: K
authors.lastname: Oshima
mesh_terms: D000478:Alkylation; D000586:Amination; D002384:Catalysis; D003500:Cyclization; D005609:Free Radicals / Q000737:chemistry; D008024:Ligands; D015394:Molecular Structure; D010720:Phosphines / Q000138:chemical synthesis* / Q000737:chemistry; D012238:Rhodium / Q000737:chemistry*; D013440:Sulfides / Q000737:chemistry
chemical_list: D005609:Free Radicals; D008024:Ligands; D010720:Phosphines; D013440:Sulfides; D012238:Rhodium; C044646:phosphine