Thioketen‐Synthesen, VII. Thioketene durch [3 + 2]‐Cycloreversion von 1,3‐Dithiolan‐Derivaten

Schaumann, Ernst; Scheiblich, Stefan; Wriede, Ulrich; Adiwidjaja, Ḡunadi

doi:10.1002/cber.19881210624

Cited by 21 publications

(2 citation statements)

References 44 publications

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“…74 In the reaction of alkynyl thiolates (39) with excess diethylamine, the amine provides the proton to generate an aldothioketene (40) and, at the same time, serves as the trapping reagent (Scheme 9). Thus, aldol-type reactions are feasible and proceed with high erythro selectivity providing (30),65 or even allowing optically active products (el Volume 2, Chapter 1.…”

Section: Thioacylation With Dithiocarboxylatesmentioning

confidence: 99%

Synthesis of Thioamides and Thiolactams

Schaumann

1991

Comprehensive Organic Synthesis

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Section: Thioacylation With Dithiocarboxylatesmentioning

confidence: 99%

Synthesis of Thioamides and Thiolactams

Schaumann

1991

Comprehensive Organic Synthesis

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“…5b However, some useful applications of thioketenes have been reported, such as the oxidation of sterically hindered thioketenes to form α-thiolactones, 6 a [2+1] cycloaddition with carbenes to form alkylidenethiiranes, 7,8 a [2+2] cycloaddition with azomethines to form β-thiolactams, 9 and 1,3dipolar cycloaddition reactions with diazoalkanes 10 or nitrile oxides. 11…”

Section: Introductionmentioning

confidence: 99%

Alkynyl Silyl Sulfides as Versatile Thioketene Equivalents

Spanka

Schaumann

2014

Synlett

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This account covers the chemistry of alkynyl silyl sulfides and their use as substitutes for aldothioketenes. In contrast to the latter heterocumulenes, which can only be prepared and used in situ, many alkynyl silyl sulfides are stable at room temperature. Exceptions are bissilylated derivatives that are capable of rearranging to form the corresponding thioketenes. This reaction is promoted thermally or by the addition of silyl-accepting Lewis bases, but is suppressed by bulky S-silyl substituents. The reactivity of the highly electrophilic alkynyl silyl sulfides is comparable to that of the corresponding ketenes and thioketenes. Nucleophiles usually add to the alkyne α-carbon atoms to give, after desilylation, thiocarbonyl compounds. Particularly useful are the reactions with amines, imines, or ynamines, which give thioamides, β-thiolactams, and cyclobutenethiones, respectively. These transformations proceed under mild conditions and provide access to derivatives that could not previously be prepared by classical means. The scope of the [2+2]-cycloaddition reaction with imines to give β-thiolactams can be expanded by using Lewis acid catalysts, particularly zinc iodide. The mechanism of this reaction has been elucidated by careful characterization of byproducts. Further modifications of the β-thiolactams prepared by this methodology are also described. Reactions of alkynyl silyl sulfides with cyclic imines lead to bicyclic systems that can be considered as thio analogues of the core structures of β-lactam antibiotics. However, there is a competition from the ringexpansion reaction to form seven-membered thiolactams and dithiolactones.

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Thioketone und Enthiolate durch 1,3‐anionische Cycloreversion von Dithiolan‐Derivaten

Schaumann

Rühter

1988

Chem. Ber.

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Die reaktiven (ar)aliphatischen Thioketone 3a-c lassen sich durch Cycloreversion der Anionen 2 von 1,3-DithioIan-4,5-dicarbonsaureestem 1 freisetzen und mit Mesitonitriloxid (S) in einer rung der Anionen 12 von 1,3-Dithiolan-l,ldioxiden 11 lassen sich die Thioketone 3a,c mit a-Wasserstoff in situ zu Enthiolaten 13 deprotoniert werden. Die Anionen 13 na@eren mit dem Nitriloxid 5 unter Addition. zu Thiohydroximsiiureatem 8. The reactive (=)aliphatic thioketones 3a-c are generated by cycydithiolane l,l-dioxides 11, thiobenzophenone (36) and t~ocam-phor (34 are isolated, whereas thioketona 3 %~ with a-hydrogen are deprotonated in situ to provide enethiolates 13. Anions 13 add nitrile oxide 5 to yield thiohydroximates 8.1 ,3dip0lUen Cycloaddition zu abfangen.der Framentie-cloreversion of the anions 2 of 1,3dithiolane-4,5dicarboxylatesThiobemophenon

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Thioketen‐Synthesen, VII. Thioketene durch [3 + 2]‐Cycloreversion von 1,3‐Dithiolan‐Derivaten

Cited by 21 publications

References 44 publications

Synthesis of Thioamides and Thiolactams

Synthesis of Thioamides and Thiolactams

Alkynyl Silyl Sulfides as Versatile Thioketene Equivalents

Thioketone und Enthiolate durch 1,3‐anionische Cycloreversion von Dithiolan‐Derivaten

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