Monodentate chiral ligands phosphonites

The use of copper catalysts based on chiral phosphorus ligands to assist 1,4-additions of dialkylzinc reagents has in recent years produced major breakthroughs, with excellent enantioselectivities. A number of monodentate and bidentate phos-phoramidites, phosphites, phosphonites, and phosphines are now available as chiral ligands for alkyl transfer to a variety of cyclic and acyclic enones. So far. 

Phosphonites. - A wide variety of chiral monodentate phosphonite ligands derived from binaphthol and biphenanthrol, e.g., (28), has been obtained from the reactions of a dichlorophosphine with the corresponding biphenol, and used... 

The menthyl phosphonites and menthyl phosphinites were used for the preparation of F-chiral monodentate ligands. For example, Imamoto used menthyl phosphinite borane complexes for the synthesis of DIPAMP analogues, as shown in Scheme 6 [23]. The treatment of phosphinite borane (/ p)-8 with methyllithium. 

Reetz, M. T. Mehler G. Meiswinkel, A. Mixtures of chiral monodentate phosphites, phosphonites and phosphines as ligands in Rh-catalyzed hydrogenation of N-acyl enamines Extension of the combinatorial approach. Tetrahedron Asymmetry 2004,15,2165-2167. 

FIGURE 29.1. Examples of chiral monodentate phosphorous-containing ligands phosphites, phos-phoramides, phosphordiamides, phosphinites, phosphonites, aminophosphonites, and aminophosphines. 

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