THERMAL RACEMIZATION OF VARIOUS S-O-ANISYL S-PHENYL N-(SUBSTITUTED)SULFILIMINES

MoriyamaMasaru,; FurukawaNaomichi,; NumataTatsuo,; OaeShigeru,

doi:10.1246/cl.1976.275

Cited by 10 publications

(3 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After 24 days under these conditions, specific rotations of 2a (which is slighly decomposed) and 2b remained practically unaltered. These results suggest that these cyclic sulfilimines are configurationally more stable than the corresponding acyclic ones. , Anyway, we can assume that the degree of racemization of 2a and 2b is not significant in asymmetric reactions conducted under conditions milder than those used in these experiences.…”

mentioning

confidence: 69%

Synthesis and Diels−Alder Reactions of a New Kind of Chiral Dienophiles: Cyclic Vinyl-p-tolylsulfilimines

et al. 2000

View full text Add to dashboard Cite

A new kind of chiral dienophiles, cyclic vinyl-p-tolylsulfilimines (2a and 2b), were obtained from the corresponding (Z)-sulfinylacrylonitriles with HBF(4) and methanol. The asymmetric Diels-Alder reaction of optically pure 2a with cyclopentadiene under mild thermal or catalyzed conditions afforded only the endo-4a adduct with complete endo and pi-facial selectivities. The ability of the sulfilimine moiety to enhance the dienophilic reactivity of the double bond is similar to that of the sulfinyl group.

show abstract

mentioning

confidence: 69%

Synthesis and Diels−Alder Reactions of a New Kind of Chiral Dienophiles: Cyclic Vinyl-p-tolylsulfilimines

et al. 2000

View full text Add to dashboard Cite

show abstract

“…Recently, our studies have focused on the synthesis and stereochemistry of optically active selenium and tellurium compounds . Since selenium and tellurium are homologous to sulfur, many optically active sulfur compounds have been synthesized, , some of which have also been used for asymmetric synthesis. , However, until recently, there have been few studies on optically active selenium and tellurium compounds. − We have previously reported the synthesis and stereochemistry of optically active tricoordinated tetravalent selenium and tellurium compounds, such as selenoxides, , selenonium ylides, selenonium salts, telluronium ylides, telluronium salts, and telluroxides . However, while selenonium imides are also tricoordinated tetravalent selenium compounds, there have been few reports on optically active selenonium imides.…”

Section: Introductionmentioning

confidence: 99%

Isolation and Stereochemistry of Optically Active Selenonium Imides

et al. 1999

View full text Add to dashboard Cite

Optical resolution of racemic diaryl selenonium-N-toluene-4′-sulfonimides (rac-1a-d) by liquid chromatography using an optically active column yielded optically pure selenonium imides. The absolute configuration around the selenium atom of (-)-2,4,6-tri-tert-butyldiphenylselenonium N-toluene-4′-sulfonimide [(-)-1a] was determined to be S by X-ray crystallographic analysis, and those of the other optically active selenonium imides were determined on the basis of their specific rotations and CD spectra. The kinetics of racemization by pyramidal inversion of the optically active selenonium imides (+)-and (-)-1b and 1d were studied. The results indicated that the activation energy for the racemization of optically active selenonium imides was greater than those for sulfonium imides.

show abstract

“…Many optically active tricoordinate organic sulfur compounds have been synthesized and their properties and reactivities widely studied. − On the other hand, there are only a few reports on the synthesis and characterization of optically active tricoordinate selenium and tellurium compounds. The organic selenium and tellurium compounds can be also synthesized in optically pure form since selenium and tellurium are elements homologous with sulfur, and it is well known that many organoselenium and organotellurium compounds have structures similar to those of the corresponding sulfur compounds.…”

Section: Introductionmentioning

confidence: 99%

Syntheses and Peculiar Behavior in Solutions of Optically Active Telluronium Salts

1996

View full text Add to dashboard Cite

A diastereomeric (epimeric) mixture of ethylmethylphenyltelluronium (1S)-(+)-camphor-10-sulfonate (dia.-1) was optically resolved by fractional recrystallization into the diastereomerically pure isomers (R)(Te)-1 and (S)(Te)-1. The absolute configurations of the isomers were determined by the X-ray crystallographic analysis of (R)(Te)-1. Enantiomerically pure (R)-ethylmethylphenyltelluronium perchlorate, tetrafluoroborate, p-chlorobenzenesulfonate, bornane-10-sulfonate, tetraphenylborate, and picrylsulfonate (R)-2-7 were isolated, respectively, by anion-exchange reactions of diastereomerically pure (R)(Te)-1. The optically active telluronium salts were found to show peculiar optical properties on their specific rotations and circular dichroism spectra in solutions compared with those of the corresponding sulfonium and selenonium salts. On the basis of NMR studies, the behavior on the optical properties of the optically active telluronium salts was found to be caused by a strong solvation in polar solvents.

show abstract

THERMAL RACEMIZATION OF VARIOUS S-O-ANISYL S-PHENYL N-(SUBSTITUTED)SULFILIMINES

Cited by 10 publications

References 4 publications

Synthesis and Diels−Alder Reactions of a New Kind of Chiral Dienophiles: Cyclic Vinyl-p-tolylsulfilimines

Synthesis and Diels−Alder Reactions of a New Kind of Chiral Dienophiles: Cyclic Vinyl-p-tolylsulfilimines

Isolation and Stereochemistry of Optically Active Selenonium Imides

Syntheses and Peculiar Behavior in Solutions of Optically Active Telluronium Salts

Contact Info

Product

Resources

About