Biheteroaromatic diphosphines

Scheme 5.11 Pd- and Pt-catalysed Diels-Alder reactions with C2-symmetric biheteroaromatic diphosphines.

Ligands with Phosphine Groups Attached to the Heterocyclic Ring 3,1 Five-membered biheteroaromatic diphosphines 37... 

Ligands, structurally characterized by an atropisomeric backbone consisting of two interconnected five-membered heteroaromatic units were initially developed by Sannicolo et al. in 1996 (Figure 2). The authors recognized the oxidation potential as a good tool to evaluate the electronic availability of the phosphorous atom in this series of biheteroaromatic diphosphines (00JOC8340). The increasing order of oxidative potential determined by voltametry is N-Me-2-BlNP... 

Six-membered biheteroaromatic diphosphines ligands 3.2.1 Dipyridylphosphine ligands P-PHOS... 

Synthesis, characterization and applications in asymmetric catalysis of biheteroaromatic diphosphines and their transition metal complexes 04CCR(248)2151. 

On the other hand, the asymmetric allylation of aldehydes was also successfully performed in the presence of chiral easily available biheteroaromatic diphosphine oxides, such as tetraMe-BITIOPO, which is the precursor of the industrially produced tetraMe-BITIOP. Using this organocatalyst, the reaction afforded homoallyllic alcohols in fair-to-good yields and with enantio-selectivities of up to 95% ee, as shown in Scheme 2.50. 

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