Phosphonites Based on the Paracyclophane Backbone:  New Ligands for Highly Selective Rhodium-Catalyzed Asymmetric Hydrogenation

Zanotti‐Gerosa, Antonio; Malan, Christophe; Herzberg, Daniela

doi:10.1021/ol0166193

Cited by 56 publications

(16 citation statements)

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“…Both the reactivity and enantioselectivity observed are comparable to the best results obtained with common monodentate or bidentate Rh-phosphite catalysts, 1 and match the results achieved by PhanePhos-type ligands. 6,19 Taken together, our experimental findings support the conclusion that helical secondary structures are important elements for significant catalyst activity and enantioselectivity. In summary, salient features of these catalysts, such as their ease of preparation from readily accessible and modular building blocks, the inherent combinatorial possibilities of this supramolecular approach, as well as the excellent levels of stereocontrol, render these ligand systems attractive for practical asymmetric synthesis.…”

supporting

confidence: 78%

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Supramolecular PhanePhos-analogous ligands through hydrogen-bonding for asymmetric hydrogenation

Laungani

Breit

2008

Chem. Commun.

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confidence: 78%

“…Similar good results were obtained for the phenylalanine precursor 4 (entries 8-13, up to 98% ee). Conversely, in the case of dimethyl itaconate (5), the classical monodentate phosphite ligand 2c performed with best results (97% ee, entry 19). This again proves that there exists no ideal catalyst for all substrates.…”

mentioning

confidence: 85%

Supramolecular PhanePhos-analogous ligands through hydrogen-bonding for asymmetric hydrogenation

Laungani

Breit

2008

Chem. Commun.

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“…An enhancement of enantioselectivity may be achieved by combining a chiral backbone with binol in a matching sense. Switching from an achiral backbone to chiral paracyclophane was successful, as reported by Zanotti-Gerosa [111]. Ligands 141 b and 141 c displayed a very strong matching/mismatching effect in the Rh-catalyzed hydrogenations of methyl 2-acetamido acrylate, inducing 99% ee and 0% ee, respectively, with the stereochemistry of the product being mainly controlled by the chirality of the backbone.…”

Section: Ar = Ph R = Hsupporting

confidence: 56%

Bidentate Ligands Containing a Heteroatom–Phosphorus Bond

Kok

Au‐Yeung

Cheung

et al. 2006

The Handbook of Homogeneous Hydrogenation

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Bidentate phosphorus ligands containing one or more heteroatom-phosphorus bonds are of high interest because they are relatively easy to prepare, and because a huge multitude of inexpensive, commercially available chiral diols, diamines, amino alcohols and amino acids can serve as the scaffold. Although the heteroatoms in these scaffolds are usually electronegative in nature, the reactivity and enantioselectivity of the metal complexes based on some of these ligands are quite remarkable, and sometimes even surpass those of the complexes based on electron-rich phosphines. This chapter compiles the comprehensive data concerning the asymmetric hydrogenation of various prochiral olefins mediated by the rhodium(I) complexes of this class of chiral ligands. Aminophosphine-Phosphinites (AMPPs)The ease of synthesis from chiral amino alcohols with a wide array of derivatives in one step established its good potential in the field of asymmetric catalysis. The general preparation of "semi-symmetrical" AMPPs involves the nucleophilic attack of two equivalents of chlorophosphine in the presence of a base (Fig. 27.1). A "mixed" AMPP can also be prepared by virtue of the fact that phosphorus-based electrophiles have a strong preference for hydroxy over secondary amine or amide. Clearly, this synthetic method allows the preparation of a large variety of AMPP ligands with adjustable electronic and steric properties. Agbossou recently reviewed the state of the art of AMPPs [1]. In consideration to the modern high-throughput methods, this approach allowed a rapid combinatorial screening of various catalysts and reactions.In general, applications of AMPP have concentrated on the asymmetric hydrogenation of functionalized olefins, especially dehydroamino acids. Among 883The Handbook of Homogeneous Hydrogenation. Edited by J. G. de Vries and C. J. Elsevier

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“…For example, Reetz's binaphthol-derived ferrocene-based bisphosphonite ligand L12 has demonstrated to have excellent reactivity and enantioselectivity in the rhodium-catalyzed hydrogenation of itaconates and a-dehydroamino acid derivatives [76]. Zanotti-Gerosa's bisphosphonite ligand L13 has also been successfully applied to the asymmetric hydrogenation of a-dehydroamino acid derivatives with up to 99% ee [77].…”

Section: P-chiral Bisphosphane Ligandsmentioning

confidence: 99%

Rhodium‐Catalyzed Asymmetric Hydrogenation

Chi

Tang

Zhang

2005

Modern Rhodium‐Catalyzed Organic Reactions

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IntroductionMolecular chirality plays a very important role in science and technology. For example, the biological activity of many pharmaceuticals and agrochemicals is often associated with a single enantiomer. The increasing demand for enantiomerically pure pharmaceuticals, agrochemicals, and fine chemicals has therefore driven the development of asymmetric catalytic technologies [1, 2]. Asymmetric hydrogenation, using molecular hydrogen to reduce prochiral olefins, ketones, and imines, has become one of the most efficient, practical, and atom-economical methods for the construction of chiral compounds [3]. During the last few decades of the 20th century, significant attention was devoted to the discovery of new asymmetric catalysts, in which transition metals bound to chiral phosphorous ligands have emerged as preferential catalysts for asymmetric hydrogenation. Thousands of efficient chiral phosphorous ligands with diverse structures have been developed, and their application to asymmetric hydrogenation has been established. Indeed, many represent the key step in industrial processes for the preparation of enantiomerically pure compounds. The immense significance of asymmetric hydrogenation was recognized when the Nobel Prize in Chemistry was awarded to Knowles and Noyori.In this chapter, we focus on the rhodium-catalyzed hydrogenation and the development of chiral phosphorous ligands for this process. Although there are other chiral phosphorous ligands, which are effective for ruthenium-, iridium-, platinum-, titanium-, zirconium-, and palladium-catalyzed hydrogenation, they are not discussed in this account. However, this does not preclude complexes of other transition metals as effective catalysts for asymmetric hydrogenation. Fortunately, there are numerous reviews and books that discuss this particular aspect of asymmetric hydrogenation [3]. Chiral Phosphorous LigandsThe invention of efficient chiral phosphorous ligands has played a critical role in the development of asymmetric hydrogenation. To a certain extent, the development of asymmetric hydrogenation parallels that of chiral phosphorous ligands. The introduction of Wilkinson's homogeneous hydrogenation catalyst, [RhCl(PPh 3 ) 3 ][4], prompted the development of the analogous asymmetric hydrogenation by Knowles [5] and Horner [6] using chiral monodentate phosphine ligands, albeit with poor enantioselectivity. Kagan and Knowles each demonstrated that improved enantioselectivities could be obtained using bidentate chiral phosphine ligands. For example, Kagan and Knowles independently reported the C 2 -symmetric bisphosphine ligands, DIOP [7] and DIPAMP [8], for rhodium-catalyzed asymmetric hydrogenation. Due to its high catalytic efficiency in rhodium-catalyzed asymmetric hydrogenation of dehydroamino acids, DIPAMP was employed in the industrial production of l-DOPA [9]. Subsequently to this work, several other successful chiral phosphorous ligands were developed, as exemplified by Kumada's ferrocene ligand BPPFOH [10] and Achiwa's BPPM ligand [11]....

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Phosphonites Based on the Paracyclophane Backbone: New Ligands for Highly Selective Rhodium-Catalyzed Asymmetric Hydrogenation

Cited by 56 publications

References 12 publications

Supramolecular PhanePhos-analogous ligands through hydrogen-bonding for asymmetric hydrogenation

Supramolecular PhanePhos-analogous ligands through hydrogen-bonding for asymmetric hydrogenation

Bidentate Ligands Containing a Heteroatom–Phosphorus Bond

Rhodium‐Catalyzed Asymmetric Hydrogenation

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