Synthesis and Characterization of Boron-Containing Ferrocenyl Ligands for Asymmetric Catalysis

Kimmich, Barbara F. M.; Landis, Clark R.; Powell, Douglas R.

doi:10.1021/om960447+

Cited by 43 publications

(14 citation statements)

References 19 publications

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“…Landis et al carried out the asymmetric hydrogenation of methyl (Z)-a-acetamidocinnamate with the boron-containing ferrocenyl ligand/Rh complexes (Scheme 8.37). Relatively low ees were obtained (<55%) [56].…”

Section: Rh Ir Ru-catalyzed Hydrogenationmentioning

confidence: 92%

Unsymmetrical 1,1′‐Bidentate Ferrocenyl Ligands

You

2009

Chiral Ferrocenes in Asymmetric Catalysis

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This chapter focuses on the preparation of enantiopure 1,1 0 -unsymmetrically disubstituted ferrocenes and their applications in asymmetric catalysis. Notably, Gibson, Long, and coworkers have documented a comprehensive review on the synthesis and catalytic applications of unsymmetrical ferrocene ligands [1]. Enantiopure 1,1 0 -bidentate ferrocenyl ligands attracted much attention soon after the discovery of ferrocene, mainly due to their unique rigid binding mode and relatively straightforward synthesis. Even today, 1,1 0 -bidentate ferrocenes still serve as an important scaffold for the design of new chiral ligands. It should be noted that the symmetrical 1,1 0 -bidentate ferrocenyl ligands, a very important class of this family, are discussed in Chapter 7. In this chapter, in addition to those having two different substituents at the 1,1 0 -positions of ferrocene I, the scope of ferrocenyl ligands will also cover unsymmetrical ferrocenyl ligands bearing identical coordination groups at the 1,1 0 -positions of ferrocene (II), for example, L1a [(R,Sp)-BPPFA] (Figure 8.1).Due to the ready availability of BPPFA and its close analogs, they have been used for many catalytic asymmetric reactions. However, the corresponding work in which BPPFA and its close analogs were simply screened and unable to afford the optimal result will not be discussed in detail. This chapter will be divided into several parts based on the reaction type. Palladium-Catalyzed Asymmetric Allylic Substitution ReactionPalladium-catalyzed allylic substitution reactions have been used extensively in asymmetric carbon-carbon and carbon-heteroatom bonds formation to provide chemo-, regio-, diastereo-, and enantioselectivity [2]. The enantioselective version of this reaction has been demonstrated successfully in organic synthesis, including the Chiral Ferrocenes in Asymmetric Catalysis. Edited by Li-Xin Dai and Xue-Long Hou

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Section: Rh Ir Ru-catalyzed Hydrogenationmentioning

confidence: 92%

Unsymmetrical 1,1′‐Bidentate Ferrocenyl Ligands

You

2009

Chiral Ferrocenes in Asymmetric Catalysis

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“…NMR solvents were degassed by three freeze-thaw cycles and were stored under N 2 over 4 A ˚molecular sieves in Young's ampoules. 1 H, 13 C{ 1 H}, 11 B{ 1 H}, 11…”

Section: Experimental General Remarksmentioning

confidence: 99%

“…B, VT-1 H/11 B{ 1 H} and11 B{ 1 H} NMR were acquired on a JEOL ECP300 spectrometer operating at 300 MHz ( 1 H), at ambient temperature unless otherwise stated. The spectra were referenced to internal standards, to the residual protic solvent ( 1 H) or the signals of the solvent ( 13 C) 11. B{ 1 H} and 11 B were referenced externally relative to BF 3 •OEt 2 .…”

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confidence: 99%

Flexible scorpionates for transfer hydrogenation: the first example of their catalytic application

et al. 2008

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Rhodium and iridium complexes of flexible scorpionate ligands based on azaindole were synthesised in good yields. The complexes were characterised in solution and in the solid state. Structural characterisation revealed a B-H-metal interaction, which is retained in solution. Given the greater flexibility of the ligand and potential cooperative effect of boron, the complexes were tested for their activity in the transfer hydrogenation of ketones.

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“…Other P/N ligands derived from PPFA are 13 and 43 whilst 44 is formed from 40 (where R 1 = Ph; R 2 = R 3 = H) via imine formation, 98 45 is derived from 42 (R 1 = R 2 = H). 99 13, 100 containing a pyrazole group, and its derivatives have been used by Togni in the Rh-catalysed hydroboration of styrene. 101 Subsequent hydrolysis forms 2-phenylethanol in up to 98.5% ee and the carbonyl stretching frequency of the Rh(13)(CO)Cl catalytic complex was correlated with the observed enantioselectivity.…”

Section: P/n Ligands Ppfa 5 First Synthesised By Kumada Andmentioning

confidence: 99%

“…98 45 was used in Rh-catalysed asymmetric hydrogenation/hydroformylation. 99 It was hoped that secondary interactions between the Lewis Acidic boron and the Lewis basic functionality of a coordinated alkene would accelerate these catalyses but only moderate ee's were actually achieved.…”

Section: P/n Ligands Ppfa 5 First Synthesised By Kumada Andmentioning

confidence: 99%

The syntheses and catalytic applications of unsymmetrical ferrocene ligands

2004

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Interest in the chemistry of ferrocene remains intense, largely due to applications within catalysis. New synthetic routes to unsymmetrical ferrocene ligands have provided another facet to this area, as substituents can be designed to be electronically- and/or sterically-distinct in order to affect the environment around the catalytically-active metal centre. This critical review provides a concise summary of the synthetic routes that have been applied to the synthesis of unsymmetrical ferrocene ligands, along with a systematic survey of the applications of these ligands in homogeneous catalysis. The aim is to help the reader select a suitable ferrocenediyl ligand for a particular synthetic application, and in the synthesis of ligands that require particular structural and/or electronic features.

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Synthesis and Characterization of Boron-Containing Ferrocenyl Ligands for Asymmetric Catalysis

Cited by 43 publications

References 19 publications

Unsymmetrical 1,1′‐Bidentate Ferrocenyl Ligands

Unsymmetrical 1,1′‐Bidentate Ferrocenyl Ligands

Flexible scorpionates for transfer hydrogenation: the first example of their catalytic application

The syntheses and catalytic applications of unsymmetrical ferrocene ligands

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