Asymmetric Hydrogenation of Isobutyrophenone Using a [(Diphosphine) RuCl<sub>2</sub> (1,4-Diamine)] Catalyst

Grasa, Gabriela A.; Zanotti‐Gerosa, Antonio; Medlock, Jonathan; Hems, William P.

doi:10.1021/ol047355y

Cited by 44 publications

(31 citation statements)

References 18 publications

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“…Since the ternary composition allows for selective replacement of the individual ligands, the catalyst can be fine‐tuned 3b. For example, a binap–Ru II complex with a 1,4‐diamine ligand acts as a precatalyst for the enantioselective hydrogenation of tetralones,7a,b a substrate class which proves problematic for the conventional 1,2‐diamine‐chelated catalysts such as 5 . Application of pyridinyl amines has recently led to an efficient catalyst class for the enantioselective hydrogenation of tert ‐alkyl ketones 7c,d…”

Section: Methodsmentioning

confidence: 99%

Bifunctional Metal–Ligand Catalysis: Hydrogenations and New Reactions within the Metal–(Di)amine Scaffold

Muñiz

2005

Angew Chem Int Ed

126

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No metal–substrate interactions: A transition‐metal complex of a primary amine can serve as an efficient bifunctional metal–ligand catalyst that functions without direct interaction of the metal and the substrate. The example shows the transition‐state structure of the enantioselective reduction of acetophenone at the molecular surface of a ruthenium hydride complex bearing a diamine with one free NH2 group (O red, Ru green, N blue).

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Section: Methodsmentioning

confidence: 99%

Bifunctional Metal–Ligand Catalysis: Hydrogenations and New Reactions within the Metal–(Di)amine Scaffold

Muñiz

2005

Angew Chem Int Ed

126

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“…Die ternäre Struktur des Katalysators erlaubt eine selektive Variation einzelner Liganden, sodass eine zusätzliche Feinabstimmung möglich ist 3b. Zum Beispiel erwies sich ein Binap‐Ru II ‐Komplex mit einem 1,4‐Diaminliganden als geeigneter Präkatalysator für die enantioselektive Hydrierung von Tetralonen,7a,b einer Substratklasse, die sich für die herkömmlichen 1,2‐Diamin‐Chelatkatalysatoren wie 5 als problematisch erwies. Schließlich hat die Verwendung von Pyridinylaminen eine effiziente Katalysatorklasse für die enantioselektive Hydrierung von tert ‐Alkylketonen aufgezeigt 7c,d…”

Section: Methodsunclassified

A Materials Approach to Site‐Isolation of Grubbs Catalysts from Incompatible Solvents and m‐Chloroperoxybenzoic Acid

Mwangi

Runge

Hoak

et al. 2008

Chemistry A European J

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The development of a method for site-isolation of Grubbs second-generation catalyst from MCPBA is described. In these reactions, Grubbs catalyst was dissolved in a solvent consisting of a mixture (1:1 v/v) of 1-butyl-3-methylimidazolium hexafluorophosphate and methylene chloride and completely encapsulated within a thimble fabricated from polydimethylsiloxane (PDMS). A series of molecules that react by cross metathesis or ring-closing metathesis were added to the interior of the thimble and allowed to react. In the last step, m-chloroperoxybenzoic acid (MCPBA) dissolved in MeOH/H(2)O (1:1 v/v) was added to the exterior of the PDMS thimble. Small organic molecules diffused through the PDMS to react with MCPBA to form epoxides, but the Grubbs catalyst remained encapsulated. This result is important because Grubbs catalyst catalytically decomposes MCPBA at ratios of MCPBA to Grubbs of 3000 to 1. The yields for this two-step cascade sequence ranged from 67 to 83 %. The concept behind this sequence is that small organic molecules have high flux through PDMS but large molecules--such as Grubbs catalyst--and ionic reagents--such as MCPBA--have much lower flux through PDMS. Small molecules can thus react both outside and inside PDMS thimbles, whereas incompatible catalysts and reagents remain site-isolated from each other. This method does not require alteration of structures of the catalysts or reagents, so it may be applied to a wide range of homogeneous catalysts and reagents. To demonstrate further that the catalyst was encapsulated, the Grubbs catalyst was successfully recycled within the cascade sequence.

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“…However, [RuCl 2 (BINAP)(DAIPEN)] (BINAP=2,2′‐bis(diphenylphosphino)‐1,1′‐binaphthyl, DAIPEN=1,1‐bis(4‐methoxyphenyl)‐3‐methyl‐1,2‐butanediamine) and related catalysts do have some important limitations and are far less effective for the hydrogenation of tetralones,7j,k dialkylketones,10 bulky ketones,11 some heterocyclic ketones,12 and imines 13. Given that so many drugs, agrochemicals, materials, and natural products can be disconnected back to enantiopure secondary alcohols, it is of significant importance to extend asymmetric hydrogenation chemistry such that it is effective for every major class of substrate.…”

Section: Introductionmentioning

confidence: 99%

Enantioselective Hydrogenation and Transfer Hydrogenation of Bulky Ketones Catalysed by a Ruthenium Complex of a Chiral Tridentate Ligand

Diaz‐Valenzuela

Phillips

Gunn

et al. 2009

Chemistry A European J

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A study on the enantioselective hydrogenation of tertiary alkyl ketones catalysed by a novel class of tridentate-Ru complex is reported. In contrast to the extensively studied [RuCl(2)(diphos)(di-primary amine)] complexes, this new class of hydrogenation catalyst smoothly reduces these less reactive bulky ketones with up to 94 % ee. The same catalyst system can also selectively reduce other potentially problematic substrates such as bulky heterocyclic ketones. Unusually for a pressure hydrogenation catalyst, similar enantioselectivity can be obtained under transfer hydrogenation conditions. The transfer hydrogenations are somewhat slower than the pressure hydrogenations, but this drawback is readily overcome, since we have discovered that a microwave accelerated transfer hydrogenation of the above ketones occurs within 20 min at about 90 degrees C with similar selectivity to that obtained in the pressure hydrogenation system.

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Asymmetric Hydrogenation of Isobutyrophenone Using a [(Diphosphine) RuCl₂ (1,4-Diamine)] Catalyst

Cited by 44 publications

References 18 publications

Bifunctional Metal–Ligand Catalysis: Hydrogenations and New Reactions within the Metal–(Di)amine Scaffold

Bifunctional Metal–Ligand Catalysis: Hydrogenations and New Reactions within the Metal–(Di)amine Scaffold

A Materials Approach to Site‐Isolation of Grubbs Catalysts from Incompatible Solvents and m‐Chloroperoxybenzoic Acid

Enantioselective Hydrogenation and Transfer Hydrogenation of Bulky Ketones Catalysed by a Ruthenium Complex of a Chiral Tridentate Ligand

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Asymmetric Hydrogenation of Isobutyrophenone Using a [(Diphosphine) RuCl2 (1,4-Diamine)] Catalyst

Cited by 44 publications

References 18 publications

Bifunctional Metal–Ligand Catalysis: Hydrogenations and New Reactions within the Metal–(Di)amine Scaffold

Bifunctional Metal–Ligand Catalysis: Hydrogenations and New Reactions within the Metal–(Di)amine Scaffold

A Materials Approach to Site‐Isolation of Grubbs Catalysts from Incompatible Solvents and m‐Chloroperoxybenzoic Acid

Enantioselective Hydrogenation and Transfer Hydrogenation of Bulky Ketones Catalysed by a Ruthenium Complex of a Chiral Tridentate Ligand

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Asymmetric Hydrogenation of Isobutyrophenone Using a [(Diphosphine) RuCl₂ (1,4-Diamine)] Catalyst