Stereocontrolled thio-Claisen rearrangement of S-allylic ketene aminothioacetals by an hydroxysubstituted adjacent stereogenic centre

Beslin, Pierre; Lelong, B.

doi:10.1016/s0040-4020(97)10178-8

Cited by 12 publications

(2 citation statements)

References 54 publications

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“…A related rearrangement has been described by Beslin. 6 The conversion of (S)-allyl thioamide acetal 3 gave the corresponding syn-thioamides 4 in a ratio of 98:2 and about 70% yield. The stereochemical outcome was interpreted as a stereoelectronic effect which favored the arrangement of the allyl subunit syn to the OH function.…”

Section: Methodsmentioning

confidence: 99%

Recent Advances in Asymmetric [3,3]-SigmatropicRearrangements

Nubbemeyer¹

2003

Synthesis

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A s y m m e t r i c [ 3 , 3 ] -S i g m a t r o p i c R e a r r a n g e m e n t s Udo Nubbemeyer Abstract: The synthesis of new complex structures is still a challenge in preparative organic chemistry. Focusing on the generation of defined stereogenic centers, the [3,3]-sigmatropic rearrangements are known as reliable reactions. Always, a highly ordered transition state must be passed through, which allows the shift of chiral information from the reactant into the nascent product. Generally, the complete [1,3]-and, frequently, the [1,4]-chirality transfer enables one to predict the configuration of the new centers.This review focuses on Claisen and Cope rearrangements, which adopt the chiral information via a so termed asymmetric induction. This means, that the directing chiral subunit is placed outside of the six centers of the rearrangement system being reorganized during the course of the [3,3]-sigmatropic reaction.

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Section: Methodsmentioning

confidence: 99%

Recent Advances in Asymmetric [3,3]-SigmatropicRearrangements

Nubbemeyer¹

2003

Synthesis

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“…Compared to them, N-α-methylbenzyl auxiliaries could reach much better results(98% de ). Several early attempts ignited the spark on stereoslective thio-Claisen rearrangement. − As central chiral auxiliaries, nonracemic thiolactam , (up to 98% de ), enantiopure alkylsulfinyl group (up to 100% de ), and 2,5-diphenylpyrrolidine(up to 99% de ) were used to control the stereochemistry. Later, axially chiral N-aryl thioamide(up to 72% de ) was applied in asymmetric thio-Claisen rearrangement.…”

Section: Introductionmentioning

confidence: 99%

Combined Theoretical and Experimental Study on High Diastereoselective Chirality Transfer Based on [2.2]Paracyclophane Derivative Chiral Reagent

Jiang

Han

et al. 2012

J. Org. Chem.

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We report a paracyclophane N-Me thioamide chiral reagent for the asymmetric thio-Claisen rearrangement with high diasteroselectivity. Comparisons between candidate chiral reagent N-phenyl-N-([2.2]paracyclophan-4-yl)amide, N-methyl amide, N-phenyl thioamide, and N-methyl thioamide are made both by experiment and theoretical calculations to clarify the principle behind the high diasteroselectivity. Dynamic (1)H NMR phenomenon tested by varying temperature (VT) experiments has proved that N-Ph amides have triple splitting peaks, while N-Ph thioamide would reduce the number to two, further substituting the Ph to Me made dynamic phenomenon disappear. So the side chain is thought to be the most rigid in N-Me thioamide, which accounts for a structure prerequisite favoring high efficient chirality transfer. This is confirmed by theoretical calculation: remarkable energy difference exists between the Re and Si faces of the chiral molecule. To further clarify the possible pathways for thio-Claisen rearrangement, theoretical prediction is adopted. The result implies that the cisoid pathways will dominate the process. Further experiment confirmed this: with N-Me thioamide, the asymmetrical reaction affords γ-unsaturated thioamides in good yields and high diastereoselectivities up to 98%. After removing the thioamide auxiliaries under hydrolysis conditions, product β,γ-substituted chiral alcohols reached high enantiopurity of 98% ee.

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Regiocontrol of Annelation of Cyclopentene-1-thiones and Cyclopenten-1-ones to Alkenes with the Aid of (1-Alkynyl)carbene Complexes (M = Cr, W)

Aumann

Venne-Dunker

et al. 2000

Eur. J. Org. Chem.

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Bicyclic olefins containing a 1-oxy-3-thiocyclopentadiene unit were obtained with high regioselectivity from [2-(cycloalk-1-enyl)-1-alkynyl]carbene complexes 1a−d and thiols 2a−c under mild conditions. If the reaction was performed in a protic solvent like ethanol, the produced allylthiocyclopentadienes 5 spontaneously underwent a thio Claisen rearrangement to give cyclopentene-1-thione complexes 3 in 62−72% yields. In nonprotic solvents, additional cyclopentene-1-thione complexes 6 and 7 were obtained as a result

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Stereocontrolled thio-Claisen rearrangement of S-allylic ketene aminothioacetals by an hydroxysubstituted adjacent stereogenic centre

Cited by 12 publications

References 54 publications

Recent Advances in Asymmetric [3,3]-SigmatropicRearrangements

Recent Advances in Asymmetric [3,3]-SigmatropicRearrangements

Combined Theoretical and Experimental Study on High Diastereoselective Chirality Transfer Based on [2.2]Paracyclophane Derivative Chiral Reagent

Regiocontrol of Annelation of Cyclopentene-1-thiones and Cyclopenten-1-ones to Alkenes with the Aid of (1-Alkynyl)carbene Complexes (M = Cr, W)

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