Catalytic Enantioselective Desymmetrization of <i>meso</i>-<i>N</i>-Acylaziridines with TMSCN

Mita, Tsuyoshi; Fujimori, Ikuo; Wada, Reiko; Wen, Jianfeng; Kanai, Motomu; Shibasaki, Masakatsu

doi:10.1021/ja053486y

Cited by 114 publications

(45 citation statements)

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“…119) There are, however, few catalytic asymmetric synthetic methods. 120,121) Our synthesis started with (S)-61a and (S)-61b. Both olefin hydrogenation and debenzylation of (S)-61a using Pd(OH) 2 -C, followed by protection of the resulting free amine with a carbobenzyloxy (Z) group, afforded the cyclic anti-b-amino acid derivative (S,S)-74 in 88% yield as a nearly optically pure compound (99% ee).…”

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confidence: 99%

Transition Metal-Catalyzed Asymmetric Reactions Using P-Chirogenic Diaminophosphine Oxides: DIAPHOXs

Nemoto

2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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This review describes the development of a new class of chiral phosphorus ligands: amino acid-derived Pchirogenic diaminophosphine oxides, DIAPHOXs, and their application to several transition metal-catalyzed asymmetric allylic substitution reactions. Pd-catalyzed asymmetric allylic alkylation with cyclic b b-keto esters as prochiral nucleophiles was initially examined using P-chirogenic diaminophosphine oxide 1a, resulting in highly enantioselective construction of quaternary stereocenters. Mechanistic investigations revealed that 1a is activated by N,O-bis(trimethylsilyl)acetamide-induced tautomerization to afford a trivalent diamidophosphite species 13, which functions as the actual ligand. Pd-catalyzed asymmetric allylic substitutions of both acyclic and cyclic substrates were also examined using various nucleophiles such as malonate derivatives, nitromethane, aliphatic amines, and aromatic amines, providing a variety of chiral compounds with good to excellent enantioselectivity. In addition, Ir-catalyzed asymmetric allylic amination and alkylation of terminal allylic carbonates were examined using structurally optimized P-chirogenic diaminophosphine oxides, and the corresponding branched products were obtained in a highly regio-and enantioselective manner. Furthermore, the developed catalytic asymmetric process was successfully applied to the catalytic enantioselective synthesis of biologically active compounds, (R)-preclamol, (R)-baclofen hydrochloride, and (؊)-paroxetine.

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confidence: 99%

Transition Metal-Catalyzed Asymmetric Reactions Using P-Chirogenic Diaminophosphine Oxides: DIAPHOXs

Nemoto

2008

CHEMICAL & PHARMACEUTICAL BULLETIN

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“…45) Recently, we reported the first catalytic enantioselective ring-opening reaction of meso-aziridines by cyanide using the Gd-5 complex (Table IV). 46 to be involved in the catalyst metal/ligand 2:3 complex. TFA is believed to bridge the two gadolinium atoms of the catalyst and stabilize the enantioselective 2:3 complex (20).…”

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confidence: 99%

Chiral Poly‐Rare‐Earth‐Metal Complexes in Asymmetric Catalysis

Shibasaki

2007

ChemInform

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Asymmetric catalysis is a powerful component of modern synthetic organic chemistry. To further broaden the scope and utility of asymmetric catalysis, new basic concepts for the design of asymmetric catalysts are crucial. Because most chemical reactions involve bond-formation between two substrates or moieties, high enantioselectivity and catalyst activity should be realized if an asymmetric catalyst can activate two reacting substrates simultaneously at defined positions. Thus, we proposed the concept of bifunctional asymmetric catalysis, which led us to the design of new asymmetric catalysts containing two functionalities (e.g. a Lewis acid and a Brønsted base or a Lewis acid and a Lewis base). These catalysts demonstrated broad reaction applicability with excellent substrate generality. Using our catalytic asymmetric reactions as keys steps, efficient total syntheses of pharmaceuticals and their biologically active lead natural products were achieved. Graduate School of Pharmaceutical Sciences, The University of Tokyo, Hongo 7-3-1, Tokyo,. Reviewsuitable for use in multifunctional asymmetric catalysis. In this account, we briefly discuss the most recent advances in rare earth metal multifunctional asymmetric catalysis in our group. For more comprehensive reviews including details of our early work and the work of other groups, see other review articles. 6),7) 2. Heterobimetallic rare earth-alkali metal-BINOL (REMB) complexes. 2.1. Use of REMB complexes as a Lewis acid-Brønsted Base catalyst. Since our first report of a catalytic asymmetric nitroaldol reaction using rare earth metal complexes, 8) we have continued to develop the concept of multifunctional catalysis wherein the catalyst exhibits both Lewis acidity and Brønsted basicity. In particular, heterobimetallic complexes that contain a rare earth metal, three alkali metals and three 1,1'-bi-2-naphthols (BINOLs) offer a versatile framework for asymmetric catalysts. The structure of such a rare earth-alkali metal-BINOL complex (abbreviated as REMB; RE: rare earth metal, M: alkali metal, B: BINOL) is shown in Fig. 1 Scheme 1. Preparation methods of rare earth-alkali metal heterobimetallic complexes from various rare earth metal sources.[1]2.2. Use of REMB complexes as a Lewis acidLewis acid catalyst. In REMB heterobimetallic catalyzed reactions, only nucleophiles bearing protons with relatively low pK a values (ca. 10-19 in H 2 O), such as nitroalkanes, malonates, ketones, and thiols, were usable due to the limited Brønsted basicity of the catalysts. Nucleophiles with higher pK a values were not applicable to REMB catalysis. Recently, however, we succeeded in broadening nucleophile scope by using the same REMB heterobimetallic catalysts, but in a different reaction mode. YLi 3 tris(binaphthoxide) (YLB: RE = Y, M = Li) prepared from Y{N(SiMe 3 ) 2 } 3 was shown to efficiently promote 1,4-addition of methoxylamine to enones, producing β-amino ketones in high ee (up to 97% ee, eq. [2]).11),12) α,β-Unsaturated N-acylpyrroles as carboxylic acid derivat...

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“…[4] meso-N-4-Nitrobenzoylaziridine 4 wurden durch Trimethylsilylcyanid in hohen Ausbeuten mit guten bis sehr guten Selektivitäten zu 1,2-Amidonitrilen 6 geöffnet, die wertvolle Vorstufen für b-Aminosäuren sind (Schema 2). [5] Durch Modifizierung der Struktur des chiralen Liganden konnte die Enantioselektivität der Reaktion weiter gesteigert werden: Mit lediglich 2 Mol-% des aus Gd(OiPr) 3 und 7 als chiralem Liganden (im Verhältnis 1:2) gebildeten Katalysators wurden die Reaktionsprodukte in fast quantitativen Ausbeuten mit bis zu 99 % ee erhalten, wobei interessanterweise die entgegengesetzten Enantiomere erhalten wurden. [6] Offenbar führt der verkleinerte Abstand zwischen der Phosphinoxideinheit und der benachbarten Hydroxygruppe in 7 zu einer solchen Veränderung des Gadolinium-Ligand-Bindungsmodus, dass sich die asymmetrische Induktion der Reaktion vollständig umkehrt.…”

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“…Chrom(III)-katalysierte, enantioselektive Aziridinöffnung mit Trimethylsilylazid nach Jacobsen et al [3] Schema 2. Gadolinium-katalysierte, enantioselektive Aziridinöffnung mit Trimethylsilylcyanid nach Shibasaki et al [5,6] [*] Prof. Dr. C. Clusters abgeleitet werden. [7] Danach verhält sich 5 als vierfach koordinierender Ligand, bindet dabei aber an mindestens zwei Metallatome gleichzeitig.…”

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Katalytische enantioselektive Ringöffnungen von Aziridinen

Schneider

2009

Angewandte Chemie

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In Gegenwart eines Dimetallkatalysators mit kooperativen Metallzentren gelingen hochenantioselektive Ringöffnungen von meso‐Aziridinen 1 mit Silylnucleophilen (siehe Schema; TMS=Trimethylsilyl). Die auf diese Weise in hohen Ausbeuten und bis zu 99 % ee zugänglichen 1,2‐Azidoamide 2 und 1,2‐Amidonitrile 3 sind wertvolle Vorstufen für enantiomerenreine 1,2‐Diamine bzw. β‐Aminosäuren.magnified image

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Catalytic Enantioselective Desymmetrization of meso-N-Acylaziridines with TMSCN

Cited by 114 publications

References 21 publications

Transition Metal-Catalyzed Asymmetric Reactions Using P-Chirogenic Diaminophosphine Oxides: DIAPHOXs

Transition Metal-Catalyzed Asymmetric Reactions Using P-Chirogenic Diaminophosphine Oxides: DIAPHOXs

Chiral Poly‐Rare‐Earth‐Metal Complexes in Asymmetric Catalysis

Katalytische enantioselektive Ringöffnungen von Aziridinen

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