Diastereocontrolled reduction of cyclic β-enaminones. A new diastereoselective route to 2,6-disubstituted piperidines

Freville, S.; Delbecq, Philippe; Thuy, Vu Moc Thuy Vu Moc; Petit, H.; Celerier, J. P.; Lhommet, G.

doi:10.1016/s0040-4039(01)00770-5

Cited by 32 publications

(25 citation statements)

References 20 publications

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“…The highest stereoselectivity was observed for multiflorine on Pd/C in which 99% of equatorial alcohol was obtained [131]. The diastereoselective synthesis of 2,6-disubstituted piperidinic alkaloids can be obtained from an easily available chiral lactam [132].…”

Section: Reduction Of Enaminonementioning

confidence: 99%

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Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Negri

Kascheres

2004

Journal of Heterocyclic Chem

179

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Enaminoketones and esters are gaining increased interest, particularly cyclic-β-enaminoesters, which are known as important intermediates for the synthesis of heterocycles and natural products, because the enantioselective preparation of highly functionalized compounds is of central importance in synthetic chemistry. Enaminones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident eletrophilicity of enones. Enaminoketones and enaminonitriles have proven to be versatile building blocks for the synthesis of various heterocycles such as pyridine, pyrimidine and pyrrole derivatives. Enaminones systems have "enone" character, and may act as acceptors in both 1,2 and 1,4-additions. In this way the enaminone serves as a scaffold for annulation, and can gain access to systems such as pyrroles indolizidines, quinolizidines and perhydroindoles, all of which are common motifs in alkaloid structures. Enaminones are frequently employed as building blocks for the preparation of a variety of bicyclic compounds of biological interest and have been recently recognized as potential anticonvulsant compounds. Since a large number of developments in the use of enaminones in heterocyclic synthesis have occurred, a review of the recent developments in the synthetic approaches, covering the literature since 1995 until 2004, to these interesting molecules and their useful chemical transformations and biological activity can be considered of considerable value.J. Heterocyclic Chem., 41, 461 (2004).Enaminoketones. Introduction.The term enaminone was introduced by Greenhill to define the enamine of a 1,3-diketone, β-ketoester or similar 1,3-difunctional reagents, and is used to indicate any compound containing the conjugated system N-C=C-C=O [1]. Enaminones are versatile synthetic intermediates that combine the ambident nucleophilicity of enamines with the ambident eletrophilicity of enones. The chemistry of the enaminocarbonyl group 1 is potentially an area of considerable scope when one considers that there are present in this moiety, three nucleophilic sites (a, c and e) and two electrophilic sites (b and d) [2][3][4] (Figure 1).Theorically, primary and secondary acyclic enaminones can exist in three tautomeric forms: ketamino form, iminoenol form and oxoimino form [1][2][3]. There is also evidence that cyclic enaminones exist primarily in the enaminoketo form. A study of cyclic enaminoketones shows that these compounds have a significant steric fator in the six-membered ring. The six-membered ring enaminoketones are only slightly stronger bases than the saturated amines, whereas five-and-seven membered rings are much stronger bases than saturated amines. This has been attributed to a large steric strain present in six-membered enaminoketones [5].β-Aminoenones or enaminoketones can exist in four conformations owing to restricted rotations around the C=C double and C-C=O single bonds [3]. Enaminones with primary or secondary amino groups can exist in both Z-and E-forms. If there is a...

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Section: Reduction Of Enaminonementioning

confidence: 99%

“…Catalytic hydrogenation conditions of β-enaminoketone 227 using Raney Ni or Pd/C as catalysts, diastereoselectively led to only one diastereomer (-)-epipinidinol 228 (Figure 81) [132].…”

Section: Reduction Of Enaminonementioning

confidence: 99%

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Negri

Kascheres

2004

Journal of Heterocyclic Chem

179

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“…The method presented herein provides a new rapid access to various enantiopure pyrrolidine vinylogous amides in good yields. Such compounds, which can be prepared by Eschenmoser coupling17 or Knoevenagel‐type reactions,18 have been used as intermediates in the synthesis of many natural compounds,19 such as anisomycin,20a apomitomycin,20b mesembrenone,20c desoxoprosophylline,20d cassine,19c pinidinone,20e deoxyfebrifugine,20f and sedacryptine 20g. Optimised conditions have allowed the efficient production of 4a – c .…”

Section: Discussionmentioning

confidence: 99%

Intrinsic Organic‐Based Synthetic/Artificial Antiferromagnets

Miller

2015

Chemistry A European J

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Mn(TCNE)[C4(CN)8]1/2 (TCNE = tetracyanoethylene) and [NEt4]Mn(II)3(CN)7 have extended layers with nearest neighbor intralayer S = 5/2 and S = 1/2 spin sites that couple antiferromagnetically forming ferrimagnetic layers. These layers are uniformly connected via diamagnetic (nonmagnetic) bridging μ4-[(C4(CN)8](2-) (8.77 Å) or μ-CN (5.48 Å) ligands, respectively, that antiferromagnetic couple the ferrimagnetic layers resulting in an antiferromagnet. The Jinter/kB is -1.0 and -1.8 K (H=-JSi⋅Sj) for Mn(TCNE)[C4(CN)8]1/2 and [NEt4]Mn(II)3(CN)7, respectively. Albeit intrinsically multilayered, these antiferromagnets have the same motif as that for artificial/synthetic antiferromagnets that exhibit giant magnetoresistance (GMR) and are commercially used in many magnetic memory applications.

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“…It has been found to have antifeedant activity against spruce budworm. 44 Pinidinol has been synthesized [45][46][47] using asymmetric hydroamination/ cyclization as the key step. 48 The enantiomerically pure substrate 23 upon hydroamination/cyclization in the presence of Cp Ã 2 NdCH(TMS) 2 24 results in the formation of piperidine 25 as a single diastereomer in 89% yield.…”

Section: Asymmetric and Diastereoselective Hydroamination In Total Symentioning

confidence: 99%

Asymmetric Hydroamination and Reductive Amination in Total Synthesis

Ghorai

Tiwari

Bhattacharyya

2013

Stereoselective Synthesis of Drugs and Natural Products

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Asymmetric hydroamination (AHA) and asymmetric reductive amination (ARA) are one of the most popular strategies for enantioselective synthesis of chiral amines, which are very important from a synthetic and a biological point of view. The addition of the NH bond across an unsaturated CC bond is known as hydroamination. AHA is ideal for industrial processes as it is a 100% atom‐economic reaction and involves readily available substrates. For broadening its scope for a variety of substrates, many metal‐based as well as metal‐free catalytic systems have been developed for asymmetric hydroamination. Along with the synthesis of functionalized chiral amines, AHA has served as a key strategy in the synthesis of the core of various natural products like codeine, pseudodistomin, swainsonine and of drugs like pentazocine. Reductive amination is a widely used efficient synthetic protocol to install an amine group in place of a carbonyl group in an organic compound. The reaction proceeds through the formation of imine and subsequent one‐pot reduction of it to give the product amine. Use of a metal‐chiral ligand combination, chiral Brønsted acid or chiral organocatalyst, or chiral auxiliary in the reaction can give rise to chiral amine products that are often valuable synthetic intermediates en route to many drugs and natural products. Application of these protocols in the total synthesis of drugs and natural products will be discussed along with some experimental procedures.

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Diastereocontrolled reduction of cyclic β-enaminones. A new diastereoselective route to 2,6-disubstituted piperidines

Cited by 32 publications

References 20 publications

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Recent development in preparation reactivity and biological activity of enaminoketones and enaminothiones and their utilization to prepare heterocyclic compounds

Intrinsic Organic‐Based Synthetic/Artificial Antiferromagnets

Asymmetric Hydroamination and Reductive Amination in Total Synthesis

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