New Chiral Diphosphine Ligands Designed to have a Narrow Dihedral Angle in the Biaryl Backbone

Saito, Takao; Yokozawa, Tohru; Ishizaki, Takero; Moroi, Takashi; Sayo, Noboru; Miura, Takashi; Kumobayashi, Hidenori

doi:10.1002/1615-4169(20010330)343:3<264::aid-adsc264>3.0.co;2-t

Cited by 452 publications

(278 citation statements)

References 6 publications

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“…Ruthenium complexes of binap [140] and derivatives, such as tol-binap [141] and segphos, [142] are used as catalysts. Industrial development of these reactions up to the ton scale was advanced by Takasago Inc. in Japan.…”

Section: Asymmetric Hydrogenation Of Ketonesmentioning

confidence: 99%

Industrial Methods for the Production of Optically Active Intermediates

Breuer¹,

Ditrich²,

Habicher³

et al. 2004

Angew Chem Int Ed

1,320

625

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Enantiomerically pure amino acids, amino alcohols, amines, alcohols, and epoxides play an increasingly important role as intermediates in the pharmaceutical industry and agrochemistry, where both a high degree of purity and large quantities of the compounds are required. The chemical industry has primarily relied upon established chemical methods for the synthesis of these intermediates, but is now turning more and more to enzymatic and biotechnological fermentation processes. For the industrial implementation of many transformations alternative methods are available. The advantages of the individual methods will be discussed herein and exemplified by syntheses of relevant compounds.

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Section: Asymmetric Hydrogenation Of Ketonesmentioning

confidence: 99%

Industrial Methods for the Production of Optically Active Intermediates

Breuer¹,

Ditrich²,

Habicher³

et al. 2004

Angew Chem Int Ed

1,320

625

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“…An axially chiral SEGPHOS efficiently discriminates two enantiofaces of a-and b-keto esters in the Ru-catalyzed hydrogenation. 80 The small angle, 65 , between the two aryl planes (dihedral angle) of the SEGPHOS-Ru complex may cause the high stereoselectivity. BPPM 81 and JOSIPHOS 82 are original for the design of C 1 -chiral diphosphines, whereas the origin of their efficiency is hard to rationalize.…”

Section: Hydrogenation Of Simple Olefins With Iridium Catalystsmentioning

confidence: 99%

Ligand Design for Catalytic Asymmetric Reduction

Ohkuma¹,

Kitamura²,

Noyori³

2006

New Frontiers in Asymmetric Catalysis

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“…Although this experiment gave complete regioselectivity[5] (4-silyloxy/5-silyloxy ≥ 99:1), the enantioselectivity (16% ee for the 4-silyloxy derivative) remained low. Surprisingly, the low enantioselectivity was improved significantly by simply increasing the size of the silyl group (1aγ1bγ1c): Up to 98% ee in the presence of Cu I -segphos [6] and > 99% ee with [Cu(MeCN) 4 -(difluorophos)]PF 6 [7] were attained in the reaction of the triisopropylsilyl derivative 1c (Table 1). …”

mentioning

confidence: 99%

“…The reactivity of the diene was increased, and (2Z,4E)-3-trimethylsilyloxy-2,4-hexadiene [4] (1a) was examined in the presence of a catalytic amount of [Cu(MeCN) 4 (segphos)]PF 6 . Although this experiment gave complete regioselectivity[5] (4-silyloxy/5-silyloxy ≥ 99:1), the enantioselectivity (16% ee for the 4-silyloxy derivative) remained low.…”

mentioning

confidence: 99%

Catalytic Asymmetric Nitroso‐Diels–Alder Reaction with Acyclic Dienes

Yamamoto

2005

Angew Chem Int Ed

114

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Keywords amino alcohols; asymmetric catalysis; cycloaddition; dienes; nitroso compoundsThe nitroso-Diels-Alder reaction has long been a valuable synthetic operation for multistep syntheses given that the resulting adducts serve as 1-amino-4-hydroxy-2-ene derivatives after a single step. Subsequent to earlier studies by Kresze and co-workers[1] on the use of simple nitroso derivatives, many research groups have made significant contributions to the steady improvement of this methodology.[2] Recently, we enhanced this transformation to catalytic and enantioselective methods through the use of nitrosopyridine as a dienophile in the presence of a chiral copper catalyst.[3] Unfortunately, the new asymmetric reaction did not proceed as smoothly for acyclic dienes as it did for cyclic systems, which therefore limits its range of application. Herein, we report catalytic regio-, diastereo-, and enantioselective nitroso-Diels -Alder reactions of acyclic 2-silyloxy-1,3-dienes that have a broad substrate scope. The pathway for the present catalytic enantioselective transformation is outlined in Scheme 1.The nitroso-Diels-Alder reaction of pentadiene and 6-methyl-2-nitrosopyridine in the presence of [Cu(MeCN) 4 -(segphos)]PF 6 gave a mixture of 1-and 4-amino derivatives in a 3:1 ratio with up to 10% ee. The reactivity of the diene was increased, and (2Z,4E)-3-trimethylsilyloxy-2,4-hexadiene[4] (1a) was examined in the presence of a catalytic amount of [Cu(MeCN) 4 (segphos)]PF 6 . Although this experiment gave complete regioselectivity[5] (4-silyloxy/5-silyloxy ≥ 99:1), the enantioselectivity (16% ee for the 4-silyloxy derivative) remained low. Surprisingly, the low enantioselectivity was improved significantly by simply increasing the size of the silyl group (1aγ1bγ1c): Up to 98% ee in the presence of Cu I -segphos [6] and > 99% ee with [Cu(MeCN) 4 -(difluorophos)]PF 6 [7] were attained in the reaction of the triisopropylsilyl derivative 1c (Table 1).

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New Chiral Diphosphine Ligands Designed to have a Narrow Dihedral Angle in the Biaryl Backbone

Cited by 452 publications

References 6 publications

Industrial Methods for the Production of Optically Active Intermediates

Industrial Methods for the Production of Optically Active Intermediates

Ligand Design for Catalytic Asymmetric Reduction

Catalytic Asymmetric Nitroso‐Diels–Alder Reaction with Acyclic Dienes

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