Asymmetric hydroxylation of enolates with N-sulfonyloxaziridines

Davis, Franklin A.; Chen, Bang Chi

doi:10.1021/cr00013a008

Cited by 617 publications

(281 citation statements)

References 39 publications

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“…7,8,9,10 Moreover, it has been reported that oxaziridines undergo a cycloaddition reaction with a variety of heterocumulenes to afford a different set of five-membered heterocycles. 7,8,9,10,11 We have recently described a simple and highly efficient [3+2] cycloaddition reaction between a variety of aryl alkenes 12 or alkynes 13 and 2-alkyl-3-aryloxaziridines. This new behaviour led to 2-alkyl-3,5-diarylisoxazolidines and 2-alkyl-3,5-diarylisoxazolines, respectively, as shown in Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

[3+2] Cycloaddition reaction between aliphatic alkynes and oxaziridines

Troisi¹,

Fabio²,

Rosato³

et al. 2010

Arkivoc

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Section: Introductionmentioning

confidence: 99%

[3+2] Cycloaddition reaction between aliphatic alkynes and oxaziridines

Troisi¹,

Fabio²,

Rosato³

et al. 2010

Arkivoc

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“…Epoxidation of olefins by N-sulfonyl oxaziridines, developed by Davis, has become a widely used reaction [7]. Transition-state structures in which oxygen transfer occurs with simultaneous N-O and C-O bond breaking or with N-O bonds significantly leading C-O bond cleavage have been suggested.…”

Section: Oxygen Transfer From An Oxaziridine To a Double Bondmentioning

confidence: 99%

“…In order to more fully evaluate the reaction trajectory, an investigation of a differently structured system was carried out (7). Because analytical difficulties precluded the use of double labeling to evaluate the molecularity of the reaction, the conversion was carried out in the presence of an intermolecular reporter (7).…”

Section: Oxygen Transfer From An Oxaziridine To a Double Bondmentioning

confidence: 99%

“…Because analytical difficulties precluded the use of double labeling to evaluate the molecularity of the reaction, the conversion was carried out in the presence of an intermolecular reporter (7). If the reaction were intermolecular, the expected products would be the epoxide sulfonimine and the epoxide sulfonamide.…”

Section: Oxygen Transfer From An Oxaziridine To a Double Bondmentioning

confidence: 99%

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Mechanisms and consequences of oxygen transfer reactions

Beak¹,

Anderson²,

Jarboe³

et al. 2000

Pure and Applied Chemistry

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Abstract:The geometry about oxygen in the transition-state structures for oxygen transfers from a nitrone to phosphorous, from a percarboxylic acid to a carbon-carbon double bond, and from an N-sulfonyl oxaziridine to a carbon-carbon double bond have been evaluated by the endocyclic restriction test. The former can proceed at an oblique angle, while the latter two require a large angle between the entering and leaving groups on oxygen. This information is used to determine the mechanism of the aldehyde-dependent oxygen transfer from molecular oxygen to a carbon-carbon double bond.Many chemical reactions, when broken down to their elementary steps, are atom transfer processes. Proper descriptions of the pathways of these reactions require experimental determinations of the arrangement of atoms in transition-state structures. With this information in hand, an informed choice between alternative pathways may be made, and understanding of the mechanism can be developed.The endocyclic restriction test is based on work by Eschenmoser, who investigated nucleophilic substitution of carbon and Hogg and Vipond who investigated nucleophilic displacements at sulfur [1][2][3]. We have used this approach to evaluate the orientation of atoms in transition-state structures for reactions in which the atom Y is transferred from the leaving group L to a nucleophile N. The test determines whether the transfer of Y from L to N can occur in an endocyclic ring. The size of the ring restricts the bond angles available in a transition-state structure (2) [1]. Experimentally, the approach involves determination of whether reaction (2) is intramolecular or intermolecular.For example, if a nucleophile and leaving group are linked by three methylene groups, the atom transfer could occur intramolecularly or intermolecularly (3). An intramolecular reaction would be observed if N-Y-L bond angle of approximately 120°would be accessible in a transition-state structure. If that or a smaller bond angle were not possible for the transfer of atom Y, the reaction could proceed in an intermolecular mode. In order to obtain a sound mechanistic conclusion, evaluation of a dissociative reaction would be required.

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“…A significant body of work by Davis and co-workers has identified a family of oxaziridines (figure 1) as electrophilic oxidants for the hydroxylation of enolates, 3,4 including the development of a camphorsulfonyl oxaziridine 3 as a chiral reagent, which has been employed to great effect in the synthesis of several natural products. The use of cinchona alkaloid derivatives as chiral organocatalysts for the α-hydroxylation of 1,3-ketoesters by organic peroxides was first disclosed in the patent literature by Dupont scientists, 8 also later by Jørgensen and co-workers, 9 where moderately high ee's can be attained (up to 80% using catalyst 5).…”

Section: Introductionmentioning

confidence: 99%

Delineating Origins of Stereocontrol in Asymmetric Pd-Catalyzed α-Hydroxylation of 1,3-Ketoesters

et al. 2010

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Abstract. Systematic studies of reaction conditions and subsequent optimization led to the identification of important parameters for stereoselectivity in the asymmetric α-hydroxylation reaction of 1,3-ketoesters. Enantioselectivities of up to 98% can be achieved for cyclic substrates and 88% for acyclic ketoesters. Subsequently, the combination of cyclic/acyclic ketoester, catalyst and oxidant was found to have a profound effect on reaction rates. The stereochemistry of the reaction contradicts that observed for other similar electrophilic substitution reactions.This was rationalized by transition state modeling, which revealed a number of cooperative weak interactions between oxidant, ligand and counterion, together with C-H/π interactions that cumulatively account for the unusual stereoselectivity.2

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Asymmetric hydroxylation of enolates with N-sulfonyloxaziridines

Cited by 617 publications

References 39 publications

[3+2] Cycloaddition reaction between aliphatic alkynes and oxaziridines

[3+2] Cycloaddition reaction between aliphatic alkynes and oxaziridines

Mechanisms and consequences of oxygen transfer reactions

Delineating Origins of Stereocontrol in Asymmetric Pd-Catalyzed α-Hydroxylation of 1,3-Ketoesters

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