Biaryl phosphorus compound

As shown in Sections 9.4.1 and 9.4.2, electron-deficient and coordinating alkynyl carbonyl compounds showed high reactivity in cationic rhodium(I)/biaryl bispho-sphine complex-catalyzed enantioselective [2- -2-1-2] cycloaddition. Therefore, Tanaka et al. investigated the use of alkynylphosphonates or alkynylphosphine oxides instead of alkynyl carbonyl compounds for the practical synthesis of axially chiral biaryl phosphorus compounds. The enantioselective [2- -2-1-2] cycloadditon... 

Nishida, G., Noguchi, K., Hirano, M. and Tanaka, K. (2007) Asymmetric assembly of aromatic rings to produce tetra-ortho-substituted axially chiral biaryl phosphorus compounds. Angewandte Chemie International Edition, 46(21), 3951-3954. Heller, B., Gutnov, A., Fischer, C., et al. (2007), Phosphorus-bearing axially chiral biaryls by catalytic asymmetric cross-cyclotrimerization and a first application in asymmetric hydrosilylation. Chemistry—A European Journal, 13(4), 1117-1128. 

Tri- and tetrazole aromatase inhibitors Mandelic amide Biaryl compounds Biaryl compounds Polycyclic aromatics Sulfur compounds Phosphorus compounds Nitrogen and cyano compounds... 

Due to the great importance of phosphines and phosphinites as chiral ligands for asymmetric catalysis, several hundred compounds of this type have been prepared. In this section, only those compounds which have been mentioned in this Houben-Weyl volume will be discussed. Because of their close relation to the specific topics, biaryl phosphines have already been mentioned in Section 6 and ferrocene derivatives in Section 7.1. All other phosphorus compounds are treated here. An excellent review on the synthesis of enantiomerically enriched compounds where phosphorus is a stereogenic center has recently been published73. 

Bidentate Phosphorus Ligands Supported on Atropisomeric Biaryl Backbones. Most ligands of this group contain binaphthyl or biphenyl moieties-providing an axial element of chirality. The flagship of this class of compounds is the atropisomeric diphosphane BINAP (36), whose complexes (primarily Ru(II) complexes (37)) play a pivotal role in asymmetric scale-up hydrogenations and isomerizations (Fig. 5). 

The [2 -I- 2 -I- 2] cycloaddition reaction can give rise to chiral compounds, especially biaryls [3q]. Control of the enantioselectivity in such transformations is of prime importance, notably because biaryls can be used as ligands in asymmetric catalysis. This topic is covered in detail in Chapter 9. Nowadays, cobalt still looks like a poor relation in this field, which is largely dominated by rhodium. Nevertheless, a report from Heller et al. shows for the first time that phosphorus-bearing axially chiral biaryls 9 can be formed by enantioselective benzene formation using the neomenthyl-indenyl cobalt complex II as a catalyst (Scheme 1.3) [7]. Good yields... 

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