Cycloiridated Helicenes as Chiral Catalysts in the Asymmetric Transfer Hydrogenation of Imines

0561135 - ÚOCHB 2023 RIV US eng J - Journal Article
Sakamoto, Daisuke - Gay Sánchez, Isabel - Rybáček, Jiří - Vacek, Jaroslav - Bednárová, Lucie - Pazderková, Markéta - Pohl, Radek - Císařová, I. - Stará, Irena G. - Starý, Ivo
Cycloiridated Helicenes as Chiral Catalysts in the Asymmetric Transfer Hydrogenation of Imines.
ACS Catalysis. Roč. 12, č. 17 (2022), s. 10793-10800. ISSN 2155-5435. E-ISSN 2155-5435
R&D Projects: GA ČR(CZ) GA19-10144S
Institutional support: RVO:61388963
Keywords : helicenes * iridacycles * asymmetric transfer hydrogenation * imines * chirality
OECD category: Organic chemistry
Impact factor: 12.9, year: 2022
Method of publishing: Limited access
https://doi.org/10.1021/acscatal.2c01816

The asymmetric synthesis of optically pure and conformationally locked oxabenzo[5]helicenes bearing pyridin-2-yl or isoquinolin-3-yl substituents and their transformation into the corresponding cycloiridated organometallics are described. These helically chiral Cp*IrIII(X)C,N-complexes (X = Cl, I) also contain a configurationally unstable pseudotetrahedral iridium center. This center undergoes epimerization at room temperature, and its relative stereochemistry, especially in the solid state, depends on the nature of the coordinated ligands. Cycloiridated helicenes were used in the asymmetric transfer hydrogenation of prochiral aromatic imines with formic acid/triethylamine to reach up to 96:4 er. It is assumed that the chirality transfer is controlled by the auxiliary
helix rather than the IrIII stereogenic center of the chiral iridacycles.
Permanent Link: https://hdl.handle.net/11104/0333821