Asymmetric synthesis of β-substituted alcanoic acids via highly stereoselective conjugate additions of organocopper compounds to chiral enoates

Helmchen, Günter; Wegner, Günter

doi:10.1016/s0040-4039(00)95122-0

Cited by 65 publications

(17 citation statements)

References 18 publications

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“…Reagent-controlled stereoselective amination reactions were performed with the olefins 5Ϫ7 using the chiral nosyloxycarbamate derived from Helmchen's auxiliary. [19] These reactions, which we performed using the same molar ratios of substrate:CaO:NsONHCO 2 R*, led to the expected products (Scheme 3) after 5 h with high conversions and purities, as confirmed by 1 H and 13 C NMR spectra, and in good isolated yields. Scheme 3 The diastereoisomeric ratios (dr) were determined by NMR spectroscopy and HPLC analyses performed on the crude mixtures.…”

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confidence: 70%

Aza‐MIRC Reactions of Sulfonyl‐Activated Hydroxycarbamates with α,β‐Difunctionalised Acrylates

et al. 2003

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Highly functionalised aziridines are readily obtained in high yields (up to 95%) under mild conditions from the reaction of trisubstituted olefins bearing different groups with nosyloxycarbamates in the presence of calcium oxide. We propose a possible explanation for the different reactivities observed between these olefins and the aminating agents. Reagent‐controlled stereoselective amination reactions led to the expected products with high conversions and purities. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)

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confidence: 70%

Aza‐MIRC Reactions of Sulfonyl‐Activated Hydroxycarbamates with α,β‐Difunctionalised Acrylates

et al. 2003

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“…Contrary to Helmchen and Wenger [6] [7], and Urban et al [8], even the use of the highly reactive Gilman's reagent (R,CuLi) [15], derived from 4 by reaction with 2 equiv. Contrary to Helmchen and Wenger [6] [7], and Urban et al [8], even the use of the highly reactive Gilman's reagent (R,CuLi) [15], derived from 4 by reaction with 2 equiv.…”

Section: Scheme Imentioning

confidence: 99%

“…of 5.7 ml(43.45 mmol) of abs. IR (NaCI, liquid (m, 4 H, H-C(2), H-C (6) of Ph); 9.54 (s, CHO). 6~ soh.…”

Section: (-12 (+)-I4mentioning

confidence: 99%

“…C(1)); 129.5 (arom. The residue was subjected to CC ( 4 H, H-C(2), H-C (6) of Ph). C(3), C (5)); 91.…”

Section: -[(Tert-butyl)diphenylsilyloxy]-33-dimethy~ent-l-yne (7) mentioning

confidence: 99%

“…The residue was purified by CC (petroleum ether/AcOEt 9:l): 3.2 g (70%) of 8. C(2), C (6)); 133. M.p.…”

Section: -[(Tert-butyl)diphenylsilyloxy]-33-dimethy~ent-l-yne (7) mentioning

confidence: 99%

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Synthesis and Odor of Chiral Partial Structures of Khusimone. Part 1

Sprdizer

Pichler

Hölzer

et al. 1997

Helvetica Chimica Acta

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Khusimone (1), one of the main odor‐donating compounds of vetiver oil is subject of the following study on structure/odor relationship. The omittance of the ethano bridge of the tricyclic khusimone leads to a bicyclic system. The stereoselective approach to this degraded structure is described, and the olfactory properties are studied. The key step of the synthesis of the hydrindane nucleus is based on a highly diastereoselective conjugate addition to a chiral oxo‐cyclopentene‐2‐carboxylate.

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Eine metallvermittelte, vollständig diastereofaciale Addition von Trialkylstannylmetallreagentien an α,β-ungesättigte γ-Alkoxyester

1999

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Die vollständige Kontrolle über die Seite des Angriffs bei der Addition von Stannylmetallreagentien an α,β‐ungesättigte γ‐Alkoxyester ist durch die Verwendung des geeigneten Gegenions möglich (siehe Reaktionsschema). Der stereochemische Verlauf der Addition hängt nicht von der Konfiguration an der C‐C‐Doppelbindung ab. Die Stereoselektivität ist jedoch für das Z‐Stereoisomer durchweg besser; hier erfolgt der Angriff mit Li als Gegenion zu 100 % auf der Si‐Seite, mit LiZnEt2 zu 100 % auf der Re‐Seite.

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Asymmetric synthesis of β-substituted alcanoic acids via highly stereoselective conjugate additions of organocopper compounds to chiral enoates

Cited by 65 publications

References 18 publications

Aza‐MIRC Reactions of Sulfonyl‐Activated Hydroxycarbamates with α,β‐Difunctionalised Acrylates

Aza‐MIRC Reactions of Sulfonyl‐Activated Hydroxycarbamates with α,β‐Difunctionalised Acrylates

Synthesis and Odor of Chiral Partial Structures of Khusimone. Part 1

Eine metallvermittelte, vollständig diastereofaciale Addition von Trialkylstannylmetallreagentien an α,β-ungesättigte γ-Alkoxyester

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