A triply convergent total synthesis of l(-)-prostaglandin E2

Donaldson, R. E.; Fuchs, P. L.

doi:10.1021/ja00398a048

Cited by 49 publications

(10 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…335 On the other hand, Fuchs and co-workers were able to transform the unwanted enantiomer ent-535, obtained by resolution of rac-535, by a sulfoxide−sulfenate rearrangement sequence into monosilylated diol 540, which produced intermediate 536, identical to that obtained from 535, ultimately transformed into (−)-PGE 2 (Scheme 91). 336 This rearrangement was also applied in the synthesis of carbacyclin analogues by transforming a Z allylic sulfide into an E allylic alcohol with correct stereochemistry, 337 as well as in the preparation of prostacyclin analogues with enhanced chemical stability. 338,339…”

Section: Mislow−braverman−evans Rearrangements In the Synthesis Of Bi...supporting

confidence: 55%

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

et al. 2017

View full text Add to dashboard Cite

The [2,3]-sigmatropic rearrangement of allylic sulfoxides to allylic sulfenates is a reversible process, generally shifted toward the sulfoxide. In the presence of thiophiles, the sulfenate is trapped, and allylic alcohols are obtained under mild conditions. In most cases, a good transfer of stereochemical information through an ordered transition state is obtained. Furthermore, the ease of coupling this process with other versatile, stereocontrolled reactions has enhanced the usefulness of this protocol. This review aims to provide a comprehensive survey of this rearrangement and its application in the synthesis of natural and bioactive products.

show abstract

Section: Mislow−braverman−evans Rearrangements In the Synthesis Of Bi...supporting

confidence: 55%

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

et al. 2017

View full text Add to dashboard Cite

show abstract

“…The presence of g-hydroxy groups in these vinyl sulfones allows one to control the stereochemistry of the process. The scheme given below outlines in general convergent total syntheses of natural or related compounds, viz., (7)-prostaglandin E 2 (296), 284 (+)-carbacyclin (27) 285 and (AE)-morphine (297), 286 carried out by Fuchs and coworkers. The key steps of these syntheses involve b-addition ± a-alkylation of cycloalkenyl sulfones 298 ± 300 (in the scheme, the sites of the a-and b-attacks are indicated by arrows).…”

Section: Addition At the C=c Bonds A Addition Of C-nucleophilesmentioning

confidence: 99%

“…The synthesis of prostaglandin 296 from the vinyl sulfone 298 involves only seven steps (the total yield was 13% with respect to 2-phenylthiocyclopent-3-enol 301 with ee 92%). 284 The prepara-tion of racemic cephalotaxine 302a 287,288 is worthy of notice as an example of more complicated syntheses. The scheme under consideration is of interest from the viewpoint of the diversity of chemical transformations.…”

Section: Addition At the C=c Bonds A Addition Of C-nucleophilesmentioning

confidence: 99%

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

Prilezhaeva¹

2000

Russ. Chem. Rev.

185

103

View full text Add to dashboard Cite

A graphical treatment of the tone reproduction problem in television systems satisfactorily answered by extensive experimental work, using the techniques of subjective appraisal which have been increasingly developed in recent years. Direct comparison of a reproduction and an original, with all the parameters of the system accurately known, calls, of course, for a considerable experimental effort. Such limited observations as have been made, however, suggest that the shape of the curves at least gives a good impression of the relative effects of viewing cathode-ray tubes with different values of A, and operating under, different conditions. It is not intended to draw any conclusions or express any as to what form of reproduction characteristic is most desirable. There can, however, be little doubt that there are instances where faithful reproduction is not desirable -where, in fact, the television system can improve on the eye and convey the maximum of information or enhance the asthetic value of a scene by emphasizing certain luminosity differences at the expense of others. To a large extent the value of such distortions must be a matter of personal preference.What constitutes the most desirable form of characteristic is, again, a question which calls for large-scale experiment on a subjective basis; factors such as signal-to-noise ratio and the effect of the characteristic on apparent definition have to be taken into account.Reference may be made in passing to the results of Jones's investigation into the preferences of a large number of observers in the matter of photographic prints.Q) This investigation tends to show that preferred prints are those in which the gradient of the logL,/logL, curve is approximately unity for the medium tones, and that a greater fall in the gradient is acceptable towards black. It would be unwise to assume, however, that the results obtained are necessarily applicable to television practice, where the form of the transfer characteristics and the viewing conditions are different. One general principle which does not seem to be in dispute is that, whereas a considerable tolerance exists when the reproduction is in monochrome, colour calls for a much closer approach to fidelity in luminosity reproduction.Large-area luminance range in modern aluminized cathoderay tubes, in the absence of external light, appears to offer little scope for worth-while improvement. It is worth noting, however, that the importance of good detail luminance range in determining the subjective quality of television pictures has been stressed by Law@) and other writers.Assuming that an optimum characteristic, or range of characteristics, can be defined, practical realization of the optimum raises a number of issues, e.g. the relative contributions of the transmitting and receiving apparatus to the overall result, and whether the desired objective can best be arrived at by selection of the camera or cathode-ray tube characteristic or by suitable circuit design.It is hoped that the present communication may help...

show abstract

“…Specifically it was found that E-27a,b exhibited 3 J Sn-H values of 42 and 55 Hz, while Z-27a,b had coupling constants of 67 and 90 Hz, respectively. 10 Attempts at direct coupling of R-stannylvinyl triflone Z-27a with iodobenzene or vinyl iodide 28 11 using tetrakis(triphenylphosphine)palladium(0) (17) or bis(acetonitrile)palladium dichloride (25) were unavailing. Therefore, Z-27a was reacted with iodine in dichloromethane at 25 °C to provide an 88% yield of R-iodovinyl triflone 11a.…”

Section: Resultsmentioning

confidence: 99%

Stereo- and Regiospecific Syntheses of α- and β-Substituted Vinyl and Dienyl Triflones via the Stille Reaction¹

1996

Self Cite

View full text Add to dashboard Cite

Acetylenic anions undergo efficient sulfonylation with trifluoromethanesulfonic anhydride to provide acetylenic triflones. These materials are stereospecifically converted to (Z)--iodovinyl triflones in one step via the addition of hydrogen iodide. Access to (Z)-R-iodovinyl triflones is also possible via a two-step process involving tributyltin hydride addition to the acetylenic triflones to generate (Z)-R-(tributylstannyl)vinyl triflones followed by an iododestannylation reaction. Both classes of iodovinyl triflones smoothly undergo palladium (0)-mediated Stille reactions with vinyl, aryl, heteroaryl, and acetylenic stannanes to stereospecifically provide trisubstituted vinyl and dienyl triflones.

show abstract

A triply convergent total synthesis of l(-)-prostaglandin E2

Cited by 49 publications

References 1 publication

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

Stereo- and Regiospecific Syntheses of α- and β-Substituted Vinyl and Dienyl Triflones via the Stille Reaction¹

Contact Info

Product

Resources

About

A triply convergent total synthesis of l(-)-prostaglandin E2

Cited by 49 publications

References 1 publication

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

From Allylic Sulfoxides to Allylic Sulfenates: Fifty Years of a Never-Ending [2,3]-Sigmatropic Rearrangement

Sulfones and sulfoxides in the total synthesis of biologically active natural compounds

Stereo- and Regiospecific Syntheses of α- and β-Substituted Vinyl and Dienyl Triflones via the Stille Reaction1

Contact Info

Product

Resources

About

Stereo- and Regiospecific Syntheses of α- and β-Substituted Vinyl and Dienyl Triflones via the Stille Reaction¹