Rhodium-Catalyzed Asymmetric [2 + 2 + 2] Cyclization of 1,6-Enynes with Aliphatic and Aromatic Alkenes was written by Ueda, Hiroki;Masutomi, Koji;Shibata, Yu;Tanaka, Ken. And the article was included in Organic Letters in 2017.Name: (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) This article mentions the following:
It has been established that a cationic rhodium(I)/(R)-MeO-BIPHEP complex catalyzes the asym. [2 + 2 + 2] cyclization of 1,6-enynes with aliphatic and aromatic alkenes to produce chiral cyclic dienes through β-hydride elimination from rhodacycle intermediates. Thus, obtained chiral cyclic dienes could be converted to chiral spirocompounds without racemization. In the experiment, the researchers used many compounds, for example, (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1Name: (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine)).
(R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine) (cas: 133545-16-1) belongs to chiral phosphine ligands. During the past two decades, tertiary phosphine catalysts have been applied extensively in a wide range of carbon–carbon and carbon–heteroatom bond-forming transformations. Trivalent phosphorus compounds called phosphines have a tetrahedral electron-group geometry which makes them structurally analogous to amines.Name: (R)-(6,6′-Dimethoxy-[1,1′-biphenyl]-2,2′-diyl)bis(diphenylphosphine)
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis