Phosphine-phosphoroamidite ligands

Bidentate Diphosphinite, Phosphite-Phosphinite, Diphosphite and Phosphine-Phosphoroamidite Ligands... 

Fig. 15 Phosphine-phosphoroamidite ligands 16-18. Summary of the best results obtained in the Ir-catalyzed hydrogenation quinolines using ligand 18...

A set of novel phosphine-phosphoroamidite ligands 16-18 (Fig. 15) possessing two elements of chirality have been prepared through a modular synthetic approach and successfully applied in the Ir-catalyzed asymmetric hydrogenation of... 

Recently, Zhang and coworkers developed a new phosphine-phosphoroamidite ligand based on BINAPFIOS (Figure 3.13). This ligand provided excellent enantios-electivities (up to 99%) in the Rh-catalyzed hydroformylation of vinyl arenes and vinyl acetate [39]. 

A -phosphine (SimplePhos) ligands provide similar levels of enantioselectivity than those observed with phosphoroamidite ligands for simple trisubstituted enones [23, 34, 35]. However, the scope of this type of ligands is higher, because they also facilitate the highly enantioselective 1,4-addition of trialkylaluminum species to more challenging hindered substrates (i.e. = Bu Fig. 3) and 3-aryl-... 

Besides phosphines and phosphites preferentially used as ligands in hydro-formylation, phosphoramidites have also been proposed. Phosphoramidites (sometimes also called phosphoroamidites) are a class of organic phosphorus compounds derived from phosphites in which the P-OR groups have been replaced by P-NR2 groups (Figure 2.31). Three different P-substituents produce a chiral (stereogenic) phosphorus atom. Phosphoramidites play a crucial role in the synthesis of nucleic acids [1] and have also been frequently considered as mono- or bidentate ligands in transition-metal catalysis [2]. 

Fig. 3 Representative results for the addition of trialkylaluminuni reagents to tiisubstituted cyclic enones using biaryl-based phosphoroamidite and iV-phosphine ligands...

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