Asymmetrische Katalysen, V. Enantioselektive Aminosäuresynthese durch Hydrierung prochiraler Olefine mit Rh‐Komplexen des neuen optisch aktiven chelatbildenden Phosphans Norphos

Brunner, Henri; Pieronczyk, W.; Schönhammer, Beate; Streng, Karin; Bernal, Ivan; Korp, Und Jim

doi:10.1002/cber.19811140331

Cited by 141 publications

(37 citation statements)

References 59 publications

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“…Catalytic asymmetric hydrogenation, as one of the most practical and efficient methods for the synthesis of chiral building blocks, has attracted much attention in both academia and industry. [1] Although excellent enantioselectivities have been obtained by using chiral bisphosphane ligands such as DIPAMP, [2] DIOP, [3] Chiraphos, [4] Norphos, [5] BPPM, [6] DEGphos, [7] BI-NAP, [8] DuPhos, [9] BPE, [9] BICP, [10] SpirOP, [11] PennPhos, [12] BisP*, [13] MiniPhOS, [14] Binaphane, [15] and PHANEPHOS, [16] the search for more practical and efficient ligands in terms of ease of preparation, high enantioselectivity, and high turnover number (TON) remains an important goal in asymmetric hydrogenation. Herein we report the synthesis and application of a new chiral 1,2-bisphospholane ligand, (1S,1S',2R,2R')-1,1'-di-tert-butyl-[2,2']-diphospholanyl (1; abbreviated (1S,1S',2R,2R')-TangPhos, Figure 1) in highly effi- cient rhodium-catalyzed asymmetric hydrogenation of a-(acylamino)acrylic acids, a-(acylamino)acrylic esters, and aarylenamides.…”

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confidence: 99%

A Chiral 1,2-Bisphospholane Ligand with a Novel Structural Motif: Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations

Tang

Zhang

2002

Angew. Chem. Int. Ed.

302

119

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confidence: 99%

A Chiral 1,2-Bisphospholane Ligand with a Novel Structural Motif: Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations

Tang

Zhang

2002

Angew. Chem. Int. Ed.

302

119

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“…23 Originally this route C (Scheme 1) was first exemplified by the asymmetric hydrogenation of N-[1-(dimethoxyphosphoryl)-ethenyl]-formamide 24 using the (+)-DIOP-Rh-complex to yield N-formyl-AlaP, but only in 76% ee. Other well-known ligands NORPHOS 25 or DIPAMP 26 as well as the analogous diethylester as substrate failed in the asymmetric hydrogenation reaction. The reason for that is not quite clear but may illustrate the fact that this route was not attractive for nearly 10 years.…”

Section: Resultsmentioning

confidence: 92%

“…The enantiomeric excess was determined by HPLC using a Liquid Chromatograph 1090 (Hewlett-Packard, Corvallis, OR), with CAD and Chiralizer fitted with a column CSP Chiracel OD-H, 0.46 × 6. 25 To 1-benzamido-1,2-dichloro-2-(4-fluorophenyl)-propionic acid (17.8 g, 50 mmol) suspended in benzene (50 ml) trimethylphosphite (10 ml, 84.8 mmol) was added with stirring at r.t. On standing overnight the precipitate formed was filtered off and the filtrate concentrated under reduced pressure. Ether was added and the crystals formed were filtered and recrystallized from water/methanol.…”

Section: Methodsmentioning

confidence: 99%

Enantioselective synthesis of ?-aminophosphonic acid derivatives by hydrogenation

et al. 1998

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Chiral α‐aminophosphonic acid derivatives are efficiently synthesized by asymmetric hydrogenation of the prochiral N‐acyl‐α,β‐dehydroaminophosphonates. PROPRAPHOS‐Rh‐catalysts from readily available (S)‐ and (R)‐Propranolol proved to be suitable in the homogenous reaction affording an enantiomeric excess of 87–92% with high rate. The aminophosphonic acid derivatives and precursors were fully characterized by 1H, 13C, and 31P NMR spectroscopy. Chirality 10:564–572, 1998. © 1998 Wiley‐Liss, Inc.

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“…1 H NMR (at 400 MHz) and 13 4 . Solvents used for anaerobic reactions were purified by standard procedures.…”

Section: Experimental Section General Remarksmentioning

confidence: 99%

“…[13] Both (R)-and (S)-6 can be isolated in enantiomerically pure forms using (À)-DBTA (natural form). When an equimolar mixture of rac-6 and (À)-DBTA was dissolved in ethyl acetate/chloroform, colorless precipitates formed in several hours.…”

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confidence: 99%

Palladium‐Catalyzed Intermolecular Asymmetric Hydroamination with 4,4′‐Disubstituted BINAP and SEGPHOS

Ogasawara

Sakamoto

et al. 2006

Adv Synth Catal

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BINAP or SEGPHOS, was synthesized and used for the asymmetric intermolecular hydroamination of aniline to vinylarenes with ee values of up to 85 %, and it is believed that the bulky groups on the 4,4'-positions and the narrower dihedral angle of the biaryl moiety are responsible for the ee enhancement in these reactions.Keywords: asymmetric catalysis; chiral amine; hydroamination; palladium; phosphine Asymmetric hydroamination of olefins is one of the simplest and the most atom-economical methods for the synthesis of chiral secondary amines.[1] The development of efficient asymmetric hydroamination reactions is, however, slow due to the high energy barrier of the C À N bond-forming process. Whereas Marks et al. and others carried out intramolecular asymmetric hydroamination using chiral organolanthanide catalysts, [2] Hartwig et al. and others recently reported a novel Pd-catalyzed intermolecular hydroamination of anilines to vinylarenes to afford Markovnikov addition products.[3] Asymmetric hydroamination has been explored for a few substrates, but only moderate enantioselectivities were obtained.[3a,c] Since we have recently observed significant ee enhancements of 4,4'-disubstituted BINAPs over the parent BINAP in a variety of Ru-catalyzed hydrogenation [4] and Pd-catalyzed C À C bond-forming reactions, [5] we have decided to explore the use of modified BINAPs in Pd-catalyzed asymmetric intermolecular hydroamination reactions. It is also well established that the dihedral angle of the biaryl moiety in chiral chelating phosphines can have significant effects in transition metalcatalyzed asymmetric reactions.[6] SEGPHOS (2; Figure 1), [7] which is believed to have the narrowest dihedral angle among these bisphosphines, indeed gives better ees than others in many Ru-, [7,8] Rh-, [9] Pd-, [10] and Cu-catalyzed [11] reactions. We hypothesize that more enantioselective catalysts for intermolecular hydroamination reactions can be designed by combining the potential positive effects of bulky substituents and narrow dihedral angles in biaryl-based bisphosphines. We decided to combine the 4,4'-substituent effect with the smaller dihedral angle in a SEG-PHOS system. Herein, we report the synthesis and optical resolution of new 4,4'-disubstituted SEG-PHOS (t-Bu-SEGPHOS, 2b) and the applications of 4,4'-disubstituted BINAPs 1 and SEGPHOS 2 in Pd-

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Asymmetrische Katalysen, V. Enantioselektive Aminosäuresynthese durch Hydrierung prochiraler Olefine mit Rh‐Komplexen des neuen optisch aktiven chelatbildenden Phosphans Norphos

Cited by 141 publications

References 59 publications

A Chiral 1,2-Bisphospholane Ligand with a Novel Structural Motif: Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations

A Chiral 1,2-Bisphospholane Ligand with a Novel Structural Motif: Applications in Highly Enantioselective Rh-Catalyzed Hydrogenations

Enantioselective synthesis of ?-aminophosphonic acid derivatives by hydrogenation

Palladium‐Catalyzed Intermolecular Asymmetric Hydroamination with 4,4′‐Disubstituted BINAP and SEGPHOS

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