Addition to multiple bonds

Carbonyl sulphide reacts with 5 -benzylisothiourea, giving 2-imino-4-oxo-6-thioxohexahydro-l,3,5-triazine (18 R = H), and with 5-benzyl-A -methyliso-thiourea to give the dimethyl derivative (18 R = Me). Chlorosulphonyl iso- 

The reactive thiourea AW -thiocarbonyldi-imidazole reacts with aliphatic 

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The same dichotomy was observed with hexafluorodimethylcarbene (228), formed by thermolysis of diazirine (227) at 150 °C. The carbene (228) can stabilize itself either intramolecularly to perfluoropropene (229), or intermolecularly by addition to multiple bonds. Oxirane (230) is formed with hexafluoroacetone, cyclopropene (231) with 2-butyne (66MI50800). 

The reactions of carbenes, which are apparently unique in displaying electrophilic character in strongly basic solutions, include substitution, addition to multiple bonds, and co-ordination with lone pairs of electrons to form unstable ylides. This last reaction is of obvious relevance to a consideration of the reactions of heterocyclic compounds with carbenes and will be summarized. 

In Part 2 of this book, we shall be directly concerned with organic reactions and their mechanisms. The reactions have been classified into 10 chapters, based primarily on reaction type substitutions, additions to multiple bonds, eliminations, rearrangements, and oxidation-reduction reactions. Five chapters are devoted to substitutions these are classified on the basis of mechanism as well as substrate. Chapters 10 and 13 include nucleophilic substitutions at aliphatic and aromatic substrates, respectively, Chapters 12 and 11 deal with electrophilic substitutions at aliphatic and aromatic substrates, respectively. All free-radical substitutions are discussed in Chapter 14. Additions to multiple bonds are classified not according to mechanism, but according to the type of multiple bond. Additions to carbon-carbon multiple bonds are dealt with in Chapter 15 additions to other multiple bonds in Chapter 16. One chapter is devoted to each of the three remaining reaction types Chapter 17, eliminations Chapter 18, rearrangements Chapter 19, oxidation-reduction reactions. This last chapter covers only those oxidation-reduction reactions that could not be conveniently treated in any of the other categories (except for oxidative eliminations). 

A -Heterocyclic Carbene Complexes in Additions to Multiple Bonds... 

In the sixth chapter the activation of O-H bonds of water, alcohols and carboxylic acids, and their addition to multiple bonds is reported. Since the formally oxidative addition of ROH gives rise to hydrido(hydroxo) complexes, [MH(OR)Ln] which are postulated as intermediates in many important reactions (water gas shift reaction, Wacker-chemistry, catalytic transfer hydrogenations etc.) the authors of this chapter,... 

Additions to Multiple Bonds Activated by Other Electron-withdrawing Groups. 443... 

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