Enantioselective Syntheses of Carbanucleosides from the Pauson-Khand Adduct of Trimethylsilylacetylene and Norbornadiene

Vázquez-Romero, Ana; Rodríguez, J. Jacob; Lledó, Agustí; Verdaguer, Xavier; Riéra, Antoni

doi:10.1021/ol8017352

Cited by 52 publications

(26 citation statements)

References 44 publications

(17 reference statements)

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“…In the case of the intramolecular version, some of us previously demonstrated that fulleropyrrolidines endowed with one or two propargyl groups at the C-2 position of the pyrrolidine ring (1,6enynes) undergo the PKR leading to cyclopentenones fused to the fullerene moiety. 39,40 On the other hand, there are studies in which cyclopentenones are successfully synthesized via intermolecular PKR; [41][42][43][44] although this approach is more limited since olefins without strain are poorly reactive with the exception of ethylene. 45,46 Studies on the chemical functionalization of carbon nanostructures via the PKR are rather scarce and, to our knowledge, this cycloaddition has not been studied in single-walled carbon nanotubes (SWCNTs) yet.…”

Section: Introductionmentioning

confidence: 99%

Regioselectivity of the Pauson–Khand reaction in single-walled carbon nanotubes

et al. 2018

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Chemical functionalization of nanotubes, in which their properties can be combined with those of other classes of materials, is fundamental to improve the physicochemical properties of nanotubes for potential technological applications. In this work, we theoretically and experimentally examine the Pauson-Khand reaction (PKR) on zig-zag, armchair, and chiral single-walled carbon nanotubes (SWCNTs). Our benchmarked density functional theory (DFT) calculations show that an alternative pathway to the widely accepted Magnus reaction pathway has significantly lower energy barriers, thus suggesting the use of this alternative pathway to predict whether a PKR on SWCNTs is favored or hampered. Accessible energy barriers of up to 16 kcal mol-1 are estimated and our results suggest that semiconducting SWCNTs react faster than metallic ones, although both types can be functionalized. Guided by our theoretical predictions, cyclopentenones are successfully attached to SWCNTs by heating and are, subsequently, characterized in the laboratory.

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Section: Introductionmentioning

confidence: 99%

Regioselectivity of the Pauson–Khand reaction in single-walled carbon nanotubes

et al. 2018

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“…[10,11,16] The main product reported during Rh complex-catalysed asymmetric hydroboration/oxidation of NBD is the exo-exo-2,6-diol. exoAddition to norbornadiene occurs in hydroallylation with allyl formate, [17] some Pauson-Khand reactions, [18] Ru-catalysed cycloadditions, [19] and terminal alkyne additions. [20] Aside from the hydroacylations and hydrogenation described above, only the PausonKhand reaction with enynes is endo-selective.…”

Section: Introductionmentioning

confidence: 99%

Stereoselectivity in the Rhodium‐Catalysed Reductions of Non‐Conjugated Dienes

Nguyen

Brown

2009

Adv Synth Catal

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The stereochemical course of rhodium-catalysed addition of hydrogen and catecholborane to bicycloA C H T U N G T R E N N U N G [2.2.1]heptadiene, and of hydrogen to a range of cyclic dienes has been analysed. For hydroboration, the overall catalytic reaction possesses exo-selectivity, but the initial step is endo-selective. For hydrogenation (deuteration), the first step may occur with either exo-or endo-selectivity, depending on the structure of the diene. This enables a distinction to be made between pathways involving prior dissociation of the diene, and direct addition to the complexed diene without full dissociation. The relative ease of hydrogenation of the first and second double bonds varies markedly with reactant structure, and also depends on the choice of catalyst ligands. For dicyclopentadiene, hydrogenation of the cyclopentene double bond is accompanied by rapid alkene isomerisation, as revealed by deuterium addition. The asymmetric hydrogenation of acyclic skipped mesodienes is reported, demonstrating control of relative rates of the two sequential steps, with ees of up to 53% after the first reduction.

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“…[1] In contrast, only a few highly enantioselective catalytic conjugate additions of cyanide have been realized despite the potential of such transformations in providing efficient enantioselective access to synthetically valuable chiral building blocks. [2] …”

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confidence: 99%

Structural Study‐Guided Development of Versatile Phase‐Transfer Catalysts for Asymmetric Conjugate Additions of Cyanide

et al. 2011

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New phase transfer catalysts are reported for the first example of an organocatalytic asymmetric conjugate addition of cyanide with acetone cyanohydrin. Utilizing an accessible cupreidinium salt and a cyanation reagent suitable for industrial scale, this reaction holds significant promise for practical asymmetric synthesis. Additionally, the reported catalysts were developed as a result of gaining key structural insights via X-ray analysis of a series of catalysts of varying efficiencies and asymmetric induction.

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Enantioselective Syntheses of Carbanucleosides from the Pauson-Khand Adduct of Trimethylsilylacetylene and Norbornadiene

Cited by 52 publications

References 44 publications

Regioselectivity of the Pauson–Khand reaction in single-walled carbon nanotubes

Regioselectivity of the Pauson–Khand reaction in single-walled carbon nanotubes

Stereoselectivity in the Rhodium‐Catalysed Reductions of Non‐Conjugated Dienes

Structural Study‐Guided Development of Versatile Phase‐Transfer Catalysts for Asymmetric Conjugate Additions of Cyanide

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