Catalytic Asymmetric Synthesis of 3,3′-Bisindoles Bearing Single Axial Chirality was written by Chen, Ke-Wei;Wang, Zhao-Shan;Wu, Ping;Yan, Xin-Yu;Zhang, Shu;Zhang, Yu-Chen;Shi, Feng. And the article was included in Journal of Organic Chemistry in 2020.COA of Formula: C48H29O4P This article mentions the following:
A catalytic asym. synthesis of 3,3′-bisindoles bearing single axial chirality has been established via chiral phosphoric acid (CPA)-catalyzed enantioselective addition reaction of 3,3′-bisindoles with ninhydrin-derived 3-indolylmethanols. The selection of ninhydrin-derived 3-indolylmethanols as suitable electrophiles is based on the consideration that the sym. and bulky moiety of ninhydrin would increase the steric congestion around the axis to generate stable axial chirality and avoid the generation of central chirality. By this approach, a series of 3,3′-bisindoles bearing single axial chirality were synthesized via the dynamic kinetic resolution (DKR) process in generally acceptable yields and considerable enantioselectivities. In addition, an in-depth investigation on the property (stability and rotation barrier) of the synthesized axially chiral 3,3′-bisindoles was carried out, thus providing useful information on this class of axially chiral frameworks. This approach makes use of the strategy of dynamic kinetic resolution of 3,3′-bisindoles, therefore expanding the generality and applicability of this strategy for catalytic asym. synthesis of 3,3′-bisindoles bearing single axial chirality. 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: 1043567-32-3COA of Formula: 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. Thousands of arylphosphines have been used as chiral ligands for metal-catalyzed asymmetric reactions. Over the last decade, however, and especially since 2005, considerable progress has been made in asymmetric phosphine catalysis.COA of Formula: C48H29O4P
Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis