New Catalytic Asymmetric Strategies to Access Chiral Aldehydes

Mazet, Clément

doi:10.2533/chimia.2011.802

Cited by 9 publications

(2 citation statements)

References 15 publications

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“…Very active water-soluble catalysts have been prepared recently, mostly based on Ru(II); however, other metal ions such as Rh(I) and Pd(II) have also proved useful. Iridium-based catalysts have rarely been investigated in redox isomerizations, ,,, although many iridium complexes were found to be outstandingly active in the catalysis of hydrogen transfer (some of them in aqueous systems). , …”

Section: Resultsmentioning

confidence: 99%

New Water-Soluble Iridium(I)–N-Heterocyclic Carbene–Tertiary Phosphine Mixed-Ligand Complexes as Catalysts of Hydrogenation and Redox Isomerization

et al. 2014

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Seven new [Ir(NHC)(η 4 -cod)(L)] complexes (4−9, 11) with NHC = bmim, emim, L = Cl − , H 2 O, or the water-soluble phosphines mtppms-Na, mtppts-Na 3 , and pta were synthesized and characterized. Na 2 [Ir(bmim)(η 4 -cod)(mtppts)] ( 6) and [Ir(bmim)(η 4 -cod)-(pta)]Cl (7) actively catalyzed hydrogenation of alkenoic and oxo acids in aqueous solution. These catalysts were also found to be active in the hydrogenation of highly substituted CC bonds (such as those in methylmaleic and methylfumaric acids). The stability of 6 was significantly increased by the addition of formate or oxalate. Under hydrogen, active catalysts were formed in situ from [IrCl(bmim)(η 4 -cod)], [IrCl(η 4 -cod)(emim)], or [IrCl(η 4 -cod)-(IMes)] and mtppts-Na 3 or pta. In the presence of HCOONa, [IrCl(η 4 -cod)(bmim)] + mtppts-Na 3 showed a TOF of 150 h −1 in the hydrogenation of itaconic acid in water at 60 °C, which is the highest value determined to date for a water-soluble Ir(I) hydrogenation catalyst in an aqueous system. Both 6 and 7 selectively isomerized alk-1-en-3-ols to the corresponding methyl ketones with no need for an external reducing agent such as H 2 . Furthermore, Na 2 [Ir(bmim)(η 4cod)(mtppts)] (6) was also shown to catalytically decompose aqueous formate to H 2 and bicarbonate.

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Section: Resultsmentioning

confidence: 99%

New Water-Soluble Iridium(I)–N-Heterocyclic Carbene–Tertiary Phosphine Mixed-Ligand Complexes as Catalysts of Hydrogenation and Redox Isomerization

et al. 2014

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“…[4] These have already been discussed in a previous issue of this journal. [5] In the present article, we summarize the development of two additional and complementary methods that were specifically devised to gain access to α-chiral aldehydes possessing either a tertiary or a quaternary (stereo)center.…”

Section: Introductionmentioning

confidence: 99%

Complementary Catalytic Strategies to Access ?-Chiral Aldehydes

Mazet¹

2013

Chimia

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The present article summarizes the development of two novel and complementary catalytic methods to access α-chiral aldehydes. A C 1 -symmetric chiral (P,N) ligand with a structure derived from the ubiquitous binepine scaffold has been specifically designed for the Pd-catalyzed α-arylation of aldehydes to access indane derivatives with a well-defined quaternary stereocenter in high yields and excellent enantioselectivities. In addition, a dinuclear palladium hydride catalyst has been synthesized for the isomerization of terminal and trisubstituted epoxides into aldehydes and ketones respectively. Combined experimental and theoretical investigations pointed to an unprecedented 'epoxide-opening/hydride-transfer' sequence. The mechanism also features two distinct enantio-determining steps in the kinetic resolution of racemic epoxides.

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Enantioselective Hydroformylation

2021

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Hydroformylation is powerful catalytic reaction capable of converting alkenes directly into aldehydes by addition of a formyl group and hydrogen across the double bond. Installation of the formyl group at an internal carbon establishes a chiral center, and a variety of chiral ligands may be employed to direct the enantioselectivity of the reaction. The alkene substrates are easily accessed, and the resultant aldehydes are common precursors for diverse synthetic manipulations. This chapter covers enantioselective hydroformylation from its inception, presents the most common metal precursors and ligands, and includes all examples that produce aldehydes with yields above 20% and enantioselectivity above 60:40 er. The initial discussion focuses on the mechanism and stereochemistry, and on the regio‐ and enantioselectivity‐determining steps in particular, as these are crucial for overall yield. The “Scope and Limitations” section is divided by substrate type and offers examples of exceptional catalytic systems that have been reported for each. The application of enantioselective hydroformylation to synthetic procedures is discussed by highlighting some reported examples, comparing it to other protocols that also afford chiral aldehydes, and exploring the standard experimental conditions. The intention of this review is to demonstrate the power and scope of enantioselective hydroformylation to researchers, and to provide a suitable starting point for those interested in its application to their own synthetic strategies.

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New Catalytic Asymmetric Strategies to Access Chiral Aldehydes

Cited by 9 publications

References 15 publications

New Water-Soluble Iridium(I)–N-Heterocyclic Carbene–Tertiary Phosphine Mixed-Ligand Complexes as Catalysts of Hydrogenation and Redox Isomerization

New Water-Soluble Iridium(I)–N-Heterocyclic Carbene–Tertiary Phosphine Mixed-Ligand Complexes as Catalysts of Hydrogenation and Redox Isomerization

Complementary Catalytic Strategies to Access ?-Chiral Aldehydes

Enantioselective Hydroformylation

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