Catalytic Enantioselective Mannich-Type Reactions Using a Novel Chiral Zirconium Catalyst

Ishitani, Haruro; Ueno, Masaharu; Kobayashi, Shū

doi:10.1021/ja970498d

Cited by 284 publications

(110 citation statements)

References 14 publications

(14 reference statements)

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“…4-Methyl-2-((Phenyl(phenylamino)methyl)cyclohexanone (6 6,147.6,141.8,129.11,128.3,127.3,126.86,117.5,113.7,58.42,56.7,42.4,40.89,35.92,32.2,27,21.1. Anal.…”

Section: -13mentioning

confidence: 99%

Polyethyleneglycol an efficient solvent for stereoselective synthesis of β-amino ketones via direct Mannich reaction

Bigdeli¹,

Heravi²,

Nemati³

et al. 2008

Arkivoc

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“…4-Methyl-2-((Phenyl(phenylamino)methyl)cyclohexanone (6 6,147.6,141.8,129.11,128.3,127.3,126.86,117.5,113.7,58.42,56.7,42.4,40.89,35.92,32.2,27,21.1. Anal.…”

Section: -13mentioning

confidence: 99%

Polyethyleneglycol an efficient solvent for stereoselective synthesis of β-amino ketones via direct Mannich reaction

Bigdeli¹,

Heravi²,

Nemati³

et al. 2008

Arkivoc

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“…2 Therefore, various enantioselective and diastereoselective Mannich-type reactions catalyzed by either organometallic complexes [3][4][5][6][7] or organocatalysts [8][9][10][11] have been developed over the past decade. However, for the transition-metal-catalyzed asymmetric Mannich reactions, a catalytic or stoichiometric amount of base is usually crucial for achieving full conversion in most cases of these reactions.…”

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confidence: 99%

“…26 The a,a-dicyanoolefin 6a emerged as the best scaffold for the AVM reaction, thus the reactions of 6a with a series of aldimines bearing various substituents on the aromatic ring were carried out (entries [5][6][7][8]. This investigation revealed that the enantioselectivity of this AVM was sensitive to both the steric and the electronic properties of the substituents on the phenyl ring of aldimines 1.…”

mentioning

confidence: 99%

Thieme Chemistry Journal Awardees - Where Are They Now? Bifunctional Silver Acetate Catalyzed Asymmetric Mannich-Type Reactions

Zeng¹,

Wang²,

Zhou³

2009

Synlett

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Efficient bifunctional silver acetate catalyzed three asymmetric Mannich-type reactions with high reactivity, up to >95:5 diastereoselectivities and moderate to excellent enantioselectivities (up to 97% ee). External base is not required in this bifunctional catalytic procedure, in which acetate promotes the deprotonation.Key words: bifunctional, silver acetate, Mannich reaction, asymmetric catalysis, iminesThe asymmetric Mannich reaction is one of the most powerful and widely utilized chemical transformation for the preparation of optically active b-amino carbonyl compounds and related compounds, 1 which are key chiral building blocks found in various natural products and pharmaceutically important compounds. 2 Therefore, various enantioselective and diastereoselective Mannich-type reactions catalyzed by either organometallic complexes 3-7 or organocatalysts [8][9][10][11] have been developed over the past decade. However, for the transition-metal-catalyzed asymmetric Mannich reactions, a catalytic or stoichiometric amount of base is usually crucial for achieving full conversion in most cases of these reactions. Thus, developing an efficient asymmetric Mannich reaction without extra base under mild conditions is attractive.Recently, we demonstrated that bifunctional silver acetate catalyzed asymmetric cycloaddition of azomethine ylides with electron-deficient alkenes using ferrocenyloxazoline-derived N,P-ligands. 12 The reactive metal-bound azomethine ylide dipole is formed through deprotonation by the acetate, which plays the role of base, meaning that extra base is not necessary. We envisioned that the introduction of an ion with proper basicity to the Lewis acid might be an appealing choice for the enolization of carbonyl compounds, and that the same strategy could be applied to the Lewis acid catalyzed Mannich reaction. Herein, we describe three examples of asymmetric Mannich-type reactions catalyzed by chiral silver acetate complexes, which acts as a bifunctional catalyst, with low to high diastereoselectivities and moderate to excellent enantioselectivities.Based on such considerations and on other groups' work, 13 we set out to establish whether the catalytic system depicted in Table 1 could be used to effect catalytic asymmetric Mannich reactions between acetyl acetone and N-Boc-protected arylimines 1.In our initial investigation, we found that the silver acetate-L1 system can efficiently catalyze the Mannich reaction of aldimines 1a with acetyl acetone in diethyl ether with high activity and moderate enantioselectivity (67% ee) in the absence of base (entry 1, Table 1). Encouraged by this result, an evaluation of a range of solvents on the activity and enantioselectivity was carried out (entries 1-4). The results showed that diethyl ether was superior to other solvents.When ligand (S,S P )-L2, with the same central chirality and opposite planar chirality to (S,R P )-L1, was used in this reaction to investigate the effect of planar chirality on the enantioselectivity and absolute configuratio...

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“…[37][38][39][40][41] In the course of our studies on remote asymmetric induction using chiral sulfoxides, we previously reported the lanthanoid triflate-catalyzed Mukaiyama aldol reaction of sulfinyl aldehyde 1 with silyl ketene acetals.…”

mentioning

confidence: 99%

“…[12][13][14] Chiral versions of these condensations have also been devised by the use of imines with a chiral auxiliary, [1][2][3][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] chiral ester enolate derivatives, [30][31][32][33][34][35][36] and chiral Lewis acids. [37][38][39][40][41] In the course of our studies on remote asymmetric induction using chiral sulfoxides, we previously reported the lanthanoid triflate-catalyzed Mukaiyama aldol reaction of sulfinyl aldehyde 1 with silyl ketene acetals. 42) Highly remote stereocontrol of 1 in this reaction led us to examine an enantioselective route to b-lactams by diastereoselective condensation of an aldimine 2 derived from 1 with silyl ketene acetals as well as enolates.…”

mentioning

confidence: 99%

Diastereoselective Imino-Aldol Condensation of Chiral 3-(p-Tolylsulfinyl)-2-furaldimine and Ester Enolates.

Arai

Yoneda

Masuda

et al. 2002

CHEMICAL & PHARMACEUTICAL BULLETIN

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The biological importance of b-lactams as antibiotics has stimulated the development of efficient procedures for the preparation of this class of compounds. Of the synthetic routes to b-lactams that have been reported, Lewis acid-promoted [1][2][3] and catalyzed [4][5][6][7][8][9][10][11] condensations of imines with silyl ketene acetals and imino-aldol condensations with ester enolates are powerful methods which involve the efficient construction of stereogenic centers of the b-lactam moiety.12-14) Chiral versions of these condensations have also been devised by the use of imines with a chiral auxiliary, [1][2][3][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29] chiral ester enolate derivatives, [30][31][32][33][34][35][36] and chiral Lewis acids. [37][38][39][40][41] In the course of our studies on remote asymmetric induction using chiral sulfoxides, we previously reported the lanthanoid triflate-catalyzed Mukaiyama aldol reaction of sulfinyl aldehyde 1 with silyl ketene acetals.42) Highly remote stereocontrol of 1 in this reaction led us to examine an enantioselective route to b-lactams by diastereoselective condensation of an aldimine 2 derived from 1 with silyl ketene acetals as well as enolates. We would like to report the details of this condensation using the sulfinyl furaldimine 2. 43)Initial experiments were performed with a typical silyl ketene acetal 3a in the presence of a lanthanoid triflate, which is found to be effective for the aldol condensation of the aldehyde 1. 42) In fact, the reaction using Yb(OTf) 3 proceeded smoothly; diastereoisomeric b-amino esters 4a and 6a were produced in a ratio of 1 : 1 (Table 1, entry 1).44) The use of other lanthanoid triflates did not improve the diastereoselectivity. The relative stereochemistry of the two products 4a and 6a was not determined at this stage; however, the configuration at the C(3) position was later determined (vide infra). We then turned our attention to using an ester enolate

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Catalytic Enantioselective Mannich-Type Reactions Using a Novel Chiral Zirconium Catalyst

Cited by 284 publications

References 14 publications

Polyethyleneglycol an efficient solvent for stereoselective synthesis of β-amino ketones via direct Mannich reaction

Polyethyleneglycol an efficient solvent for stereoselective synthesis of β-amino ketones via direct Mannich reaction

Thieme Chemistry Journal Awardees - Where Are They Now? Bifunctional Silver Acetate Catalyzed Asymmetric Mannich-Type Reactions

Diastereoselective Imino-Aldol Condensation of Chiral 3-(p-Tolylsulfinyl)-2-furaldimine and Ester Enolates.

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