New chiral phosphorus catalysts derived from (S)-binaphthol for highly enantioselective reduction of acetophenone by borane was written by Ma, Margaret F. P.;Li, Kangying;Zhou, Zhenghong;Tang, Chuchi;Chan, Albert S. C.. And the article was included in Tetrahedron: Asymmetry in 1999.Electric Literature of C24H22NO2P This article mentions the following:
New chiral (+)-2,2′-O,O-(1,1′-binaphthyl)-dioxo-N,N-diethylphospholidine 1 and its borane complex 3 were prepared from (S)-binaphthol and their use as catalysts in enantioselective borane reductions of prochiral acetophenone were investigated. Enantiomeric excesses of up to 98.5% have been obtained using 6 mol% of 1 at room temperature and using 6 mol% of 3 at 100°. 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: 252288-04-3Electric Literature 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. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Electric Literature of C24H22NO2P
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis