Asymmetric construction of polycyclic indoles through olefin cross-metathesis/intramolecular Friedel-Crafts alkylation under sequential catalysis was written by Cai, Quan;Zhao, Zhuo-An;You, Shu-Li. And the article was included in Angewandte Chemie, International Edition in 2009.Synthetic Route of C48H29O4P This article mentions the following:
Sequential catalytic olefin cross-metathesis of allyloxymethyl and allylaminomethyl indoles and enones followed by enantioselective Friedel-Crafts alkylation produced polycyclic indoles containing the tetrahydropyranoindole and tetrahydro-β-carboline ring systems, such as I and II, in excellent yields and excellent enantioselectivities. Chiral phosphoric acids were used as catalysts for the Friedel-Crafts alkylations of indolyl enones while both a ruthenium complex and chiral phosphoric acids were used as catalysts for sequential olefin cross-metathesis and Friedel-Crafts alkylations of allyloxymethyl or allylaminomethyl indoles and enones. In the experiment, the researchers used many compounds, for example, (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide (cas: 1043567-32-3Synthetic Route of C48H29O4P).
(11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide (cas: 1043567-32-3) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Chiral ligands coordinate to metal centers to create an asymmetric environment around the reaction centers, which eventually affects enantioselectivity and reaction rate.Synthetic Route of C48H29O4P
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis