Chiral amine–imine ligands based on trans-2,5-disubstituted pyrrolidines and their application in the palladium-catalyzed allylic alkylation

Chen, Hongfeng; Sweet, James A.; Lam, Kin Chung; Rheingold, Arnold L.; McGrath, Dominic V.

doi:10.1016/j.tetasy.2009.07.010

Cited by 25 publications

(15 citation statements)

References 56 publications

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“…1). The compounds containing 2,5-disubstituted pyrrolidine ring are also attractive to synthetic chemists by their versatile utilities in organic synthesis (Vaswani et al 2009;Lemen and Wolfe 2010;Chen et al 2009;Shu et al 2010). Some important alkaloids, such as cocaine (Lewin et al 1987;Mans and Pearson 2004), gephyrotoxin ) and monomorine (Jefford et al 1991), possess cis-2,5-disubstituted pyrrolidine ring system.…”

Section: Introductionmentioning

confidence: 99%

Efficient synthesis of unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine

Wang

Cheng

et al. 2011

Amino Acids

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Section: Introductionmentioning

confidence: 99%

Efficient synthesis of unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine

Wang

Cheng

et al. 2011

Amino Acids

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“…[5,6] Furthermore, these compounds have been used as ligands for transition metals, organocatalysts, [7][8][9] and effective chiral controllers in asymmetric synthesis. [10][11][12] It has been observed that there is a significant interest in the stereoselective synthesis of chiral pyrrolidines, using N-tert-butanesulfinyl imines as a chiral auxiliary.…”

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confidence: 99%

Asymmetric Synthesis of Pyrrolidine‐Containing Chemical Scaffolds via Tsuji–Trost Allylation of N‐tert‐Butanesulfinyl Imines

Dawood

Georgiou

Wilkie

et al. 2017

Chemistry A European J

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A simple and efficient asymmetric synthesis of novel sp3-rich pyrrolidine chemical scaffolds over five steps starting from simple ketones is described. Key steps involve the use of tert-butanesulfinamide as a chiral auxiliary to perform an asymmetric Tsuji-Trost allylation, with subsequent cross-metathesis with an acrylate ester and reduction of the sulfinimine/cyclisation of the resulting amine giving the pyrrolidine scaffolds in high yields and diastereoselectivites. By removing the chiral auxiliary and functionalising the ester group, the resulting scaffold core can be further derivatised. Introduction Compounds containing a pyrrolidine ring usually possess a wide range of biological activities such as, anticancer, antitumor and anti-biotic activity.[1] Specifically, chiral pyrrolidines constitute a large group of heterocyclic organic compounds which are useful building blocks of pharmaceuticals, [2,3] vitamins, dyes, drug candidates, hormones, agrochemicals [4] and alkaloid natural products. [5,6] Furthermore, these compounds have been used as ligands for transition metals, organocatalysts, [7][8][9] and effective chiral controllers in asymmetric synthesis. [10][11][12] It has been observed that there is a significant interest in the stereoselective synthesis of chiral pyrrolidines, using N-tert-butanesulfinyl imines as a chiral auxiliary. In particular, by the addition of Grignard reagents [13] or hydride[14] to γ-chlorinated N-tert-butanesulfinyl imines followed by cyclisation, or via Wacker-type oxidation cyclisation of alkenes with tertbutanesulfinamide nucleophiles [15] or iodocyclisation of homoallylic sulfonamides. [16] Recently, the diastereoselective α-allylation of a variety chiral α-N-tert-butanesulfinyl imines using Tsuji-Trost reaction has been reported by Stockman and co-workers.[17] In particular, under mild reaction conditions, compounds bearing an allyl group at the α-position of chiral N-tert-butanesulfinyl imines were obtained in high yields, with good diastereoselectivity and substrate tolerance. In a following report, the α-allylation of chiral N-tert-butanesulfinyl imines derived from symmetric cyclic ketones was reported.[18] Hence, we envisioned taking advantage of the Tsuji-Trost allylation of N-tert-butanesulfinyl imines to access, in five steps, pyrrolidine-based chemical scaffolds as outlined in Scheme 1. We aimed to achieve this through cross metathesis of the allylated N-tert-butanesulfinyl imines, followed by reduction and finally ring cyclisation, using an intramolecular Michael addition. Scheme 1. Outline of the asymmetric synthesis of pyrrolidine chemical scaffolds 5. Results and Discussion

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“…[1][2][3][4][5] Several structural variations in pyridylmethylamines and their complexes have been reported, [6][7][8] and the resultant steric and electronic properties are important for specific chemical applications. The majority of transition metal complexes bearing these ligands have been used in a number of investigations including synthetic, structural analysis and spectroscopic applications, [9][10][11][12] as well as for electronic materials, 4,5 catalysts for organic transformation, [13][14][15] biological applications, 16 and olefin polymerization. 17,18 In contrast, poly(methyl methacrylate) (PMMA) is a universal polymer with optical applications, and its improved optical properties are dependent on the higher glass transition temperature (T g ) and syndiotacticity of PMMA.…”

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confidence: 99%

Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N‐Methyl‐N‐((pyridin‐2‐yl)methyl)cyclohexanamine

Ahn

Shin

Nayab

et al. 2016

Bulletin Korean Chem Soc

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Transition metal complexes containing N,N 0 -bidentate pyridylmethylamines ligands continue to receive attention since these ligands can be synthesized with high coordination versatility by introducing various substituents on the amine and/or pyridyl unit. [1][2][3][4][5] Several structural variations in pyridylmethylamines and their complexes have been reported, [6][7][8] and the resultant steric and electronic properties are important for specific chemical applications. The majority of transition metal complexes bearing these ligands have been used in a number of investigations including synthetic, structural analysis and spectroscopic applications, 9-12 as well as for electronic materials, 4,5 catalysts for organic transformation, 13-15 biological applications, 16 and olefin polymerization. 17,18 In contrast, poly(methyl methacrylate) (PMMA) is a universal polymer with optical applications, and its improved optical properties are dependent on the higher glass transition temperature (T g ) and syndiotacticity of PMMA. Radical-mediated polymerization of methyl methacrylate (MMA) cannot achieve sufficiently high T g or a high syndiotacticity in PMMA. Thus, non-radicalmediated MMA polymerization that can result in a higher T g up to 140C is an active and promising field of research.19-22 Recently, we have explored various transition metal complexes as catalysts for homogeneous polymerization of MMA to produce syndiotactic PMMA with high T g up to 130C. 23,24 Considering the versatility of the pyridylbased ancillary ligands and their ability to fine-tune steric and electronic properties, we extended our investigations to the synthesis of novel Co(II), Cu(II), and Zn(II) complexes supported by specific N-methyl-N-((pyridin-2-yl)methyl) cyclohexanamine (nmpc), which shows unique activity and selectivity with several transition metals during MMA polymerization.The complexation reactions proceeded smoothly at room temperature by treating with EtOH solution of (nmpc) with stoichiometric amounts of metal starting material and afforded [M(nmpc)Cl 2 ] n (M = Co and Zn, n = 1; M = Cu, n = 2) in high yields (91-96%) (Scheme 1). The results of 1 H NMR, 13C NMR, IR, and elemental analysis were consistent with the ligands and corresponding complex formation. Particularly, the 1 H NMR spectra of Zn(II) confirmed complexation of the respective ligand; as expected, the majority of the ligand proton signals were observed at a lower field for the complexes relative to the corresponding free ligand. In addition, the incorporation of Me substituents on the N atoms of the ligand architecture resulted in enhanced solubility of corresponding complexes in organic solvents.X-ray diffraction analysis revealed that [Co(nmpc)Cl 2 ] and [Zn(nmpc)Cl 2 ] crystallized in the monoclinic system with space group P2 1 /c and existed as monomeric and solvent-free complexes. [Cu(nmpc)(μ-Cl)Cl] 2 existed as a dimer with space group P-1. The structures for [Co(nmpc)Cl 2 ], [Zn (nmpc)Cl 2 ], and [Cu(nmpc)(μ-Cl)Cl] 2 at a 50% probability level, along with ...

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Chiral amine–imine ligands based on trans-2,5-disubstituted pyrrolidines and their application in the palladium-catalyzed allylic alkylation

Cited by 25 publications

References 56 publications

Efficient synthesis of unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine

Efficient synthesis of unnatural dipeptides based on cis-2,5-disubstituted pyrrolidine

Asymmetric Synthesis of Pyrrolidine‐Containing Chemical Scaffolds via Tsuji–Trost Allylation of N‐tert‐Butanesulfinyl Imines

Polymerization of Methyl Methacrylate Catalyzed by Co(II), Cu(II), and Zn(II) Complexes Bearing N‐Methyl‐N‐((pyridin‐2‐yl)methyl)cyclohexanamine

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