1-Alkenyllithium-Reagentien mit einem Heteroatomsubstituenten in derα-Position: Carbanionen und Carbenoide zur C-C-Verknüpfung

Braun, Manfred

doi:10.1002/(sici)1521-3757(19980216)110:4<444::aid-ange444>3.0.co;2-j

Cited by 43 publications

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References 269 publications

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“…When lithiated enol ethers 1 were used as the organometallic species in the addition to nitrones 2 [12–14], either syn - or anti -configured hydroxylamine derivatives 3 were obtained, depending strongly on the reaction conditions (Table 1) [15–16]. Subsequent treatment under basic conditions with tert -butyldimethylsilyl triflate afforded TBS-protected compounds syn - and anti - 4 in good overall yields [17].…”

Section: Resultsmentioning

confidence: 99%

Addition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics

Pfrengle

Reißig

2010

Beilstein J. Org. Chem.

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SummaryA stereodivergent synthesis of enantiopure 3,6-dihydro-2H-pyrans is presented. The addition of lithiated enol ethers to carbohydrate-derived nitrones afforded syn- or anti-configured hydroxylamine derivatives 4a–d that were cyclized under Lewis acidic conditions to yield functionalized dihydropyrans cis- or trans-5a–d containing an enol ether moiety. This functional group was employed for a variety of subsequent reactions such as dihydroxylation or bromination. Bicyclic enol ether 19 was oxidatively cleaved to provide the highly functionalized ten-membered ring lactone 20. The synthesized enantiopure aminopyrans 24, 26, 28 and 30 can be regarded as carbohydrate mimetics. Trimeric versions of 24 and 28 were constructed via their attachment to a tricarboxylic acid core.

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Section: Resultsmentioning

confidence: 99%

Addition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics

Pfrengle

Reißig

2010

Beilstein J. Org. Chem.

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Efficient Palladium-Catalyzed Substitution in Enantiomerically Pure Allyl Carbonates – A Stereodivergent Access to β-Aryl-Substituted γ-Lactones and γ-Hydroxy Amides

1998

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Allyl carbonates (Z)‐8 and (E)‐9 are available from the addition of the chiral alkenyllithium reagent 5b to aromatic aldehydes 6. When sujected to a palladium‐catalyzed substitution by sodium malonate, (Z)‐carbonates 8 give diesters 10 and 11, whereas (E)‐carbonate 9 predominantly leads to the diastereomeric product 12. The latter is converted into (S)‐γ‐butyrolactone 13 in a three step sequence. When the same protocol is applied to the isomeric diesters 10 and 11, (R)‐lactones 13 result. A rationale for the stereochemical outcome of the allylic substitutions in the carbonates 10‐12 is offered, based on π‐σ‐π interconversions of the palladium complexes 20‐23.

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Asymmetric deprotonation with alkyllithium‐(–)‐sparteine

Hoppe

Christoph

2004

The Chemistry of Organolithium Compounds

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1-Alkenyllithium-Reagentien mit einem Heteroatomsubstituenten in derα-Position: Carbanionen und Carbenoide zur C-C-Verknüpfung

Cited by 43 publications

References 269 publications

Addition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics

Addition of lithiated enol ethers to nitrones and subsequent Lewis acid induced cyclizations to enantiopure 3,6-dihydro-2H-pyrans – an approach to carbohydrate mimetics

Efficient Palladium-Catalyzed Substitution in Enantiomerically Pure Allyl Carbonates – A Stereodivergent Access to β-Aryl-Substituted γ-Lactones and γ-Hydroxy Amides

Asymmetric deprotonation with alkyllithium‐(–)‐sparteine

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