Asymmetric iridium-catalyzed hydrogenation of 2-methylindole using phosphite ligands was written by Lyubimov, Sergey E.;Ozolin, Dmitry V.;Davankov, Vadim A.. And the article was included in Tetrahedron Letters in 2014.Synthetic Route of C24H22NO2P This article mentions the following:
The iridium-catalyzed asym. hydrogenation of 2-methylindole using monodentate phosphites and amidophosphites as ligands was examined The use of iodine as the additive resulted in increased enantioselectivity and conversion in the iridium-catalyzed hydrogenation of 2-methylindole. Full conversion and up to 80% ee were obtained with a catalyst based on a phosphite ligand. In the experiment, the researchers used many compounds, for example, (11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3Synthetic Route of C24H22NO2P).
(11bS)-N,N-Diethyldinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin-4-amine (cas: 252288-04-3) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Effective chiral catalysts for nucleophilic phosphine catalysis are scarce, seriously limiting the development of asymmetric variants. Synthetic Route of C24H22NO2P
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis