Highly enantioselective transfer hydrogenation of α-imino esters by a phosphoric acid was written by Kang, Qiang;Zhao, Zhuo-An;You, Shu-Li. And the article was included in Advanced Synthesis & Catalysis in 2007.Quality Control of (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide This article mentions the following:
Chiral phosphoric acids have been identified as highly efficient organocatalysts for the asym. transfer hydrogenation of α-imino esters and amide. Utilizing Hantzsch esters as the hydrogen donor, versatile highly enantioenriched α-amino esters and their derivatives were obtained with up to 98% ee. 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: 1043567-32-3Quality Control of (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide).
(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. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.Quality Control of (11bS)-4-Hydroxy-2,6-di(phenanthren-9-yl)dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis