Ethers and sulphides

There has been a series of papers on the deoxygenation of 2-nitrophenyl phenyl ethers and sulphides. Of particular interest has been the role of pentacovalent intermediates (47) in these reactions. These are certainly not the primary intermediates in the reactions but are of great importance in determining the course of the reaction. Their genesis is thought to be that shown in Scheme 3.57... 

The microstructure of polyisoprene prepared in a variety of solvents and solvent mixtures (113) has been determined. Various ethers and sulphides vary in their ability to reduce the 1,4 content of the polymer. The most effective ether was tetrahydrofuran. The presence of only two molecules per active chain was reported to reduce the 1,4 content to that observed in the pure ether. More recent investigations have failed to confirm that the requirement is as low as this 74,126) but relatively small amounts of tetrahydrofuran do markedly decrease the cis-1,4 content and increase the 3,4 content. Similar results have been obtained for butadiene 60) with respect to 1,4 and 1,2 structures. 

The pyridones (237) afford the valence isomers (238) in good yield on irradiation.A review dealing with the synthesis and photochemical reactivity of A/-subst i tuted 2(1-ff)-pyrimidones has been published. An example of hydrogen abstraction by an imine nitrogen has been reported. This follows from a study of the photochemical behaviour of the pyrimidones (239) in the presence of hydrogen donors such as ethers and sulphides. The products from this are the adducts (240) which are formed in variable yields. A study of the photodecomposition of 5,5-diethylthiobarbituric acid in aqueous and non-aqueous media has been reported. -... 

These findings represent new and significant conclusions about the relative reactivity of cyclic ethers. Prior to the work of Saegusa et al. [54], most work has suggested that a monomer s reactivity as reflected in its fep is related to basicity and/or possibly ring strain. More will be said about these results at the end of this review after data for all the cyclic ethers and sulphides have been presented. 

It seems fair to say that at the time of writing the factors influencing reactivity of cyclic ethers and sulphides are still not completely known. We can look for greater insight as more detailed and carefully controlled kinetic studies are made. 

Volume 15 deals with those polymerization processes which do not involve free radicals as intermediates. Chapters 1 and 2 cover homogeneous anionic and cationic polymerization, respectively, and Chapter 3 polymerizations initiated by Zeigler-Natta and related organometallic catalysts. Chapters 4, 5 and 6 deal with the polymerization of cyclic ethers and sulphides, of aldehydes and of lactams, respectively. Finally, in Chapter 7 polycondensation reactions, and in Chapter 8 the polymerization of AT-carboxy-a-amino acid anhydrides, are discussed. 

Dealkylation of alkyl aryl ethers and sulphides by diaryl-posphide or arsenide ions. 

We will now assume all of the species in reaction 55 are in their condensed phases and again fail to distinguish heats of vaporization and sublimation. For the sulphonyl sulphenate 46, we again use equation 47 where the ncessary value of b was derived as the sum of those for sulphones, ethers and sulphides, resulting in a predicted AHf(g, 46) value of —83 kcal mol-1. Relatedly, the value of b for sulphenic acids was taken as the sum of those for alcohols and sulphides, and thus AHf(g, 85)= —26 kcal mol-1. The left-hand side of reaction 39 is [ — 117 + ( — 26)] — [ — 83 +( — 68)] = 8 kcal mol-1 more stable than the right, where we remember that the value for PhS02—O—S—Ph is an upper bound. The results for the gaseous and condensed phases are thus seen as consonant. It is safe to say that benzenesulphonyl benzenesulfenate is best not viewed as an anhydride since its hydrolysis is endothermic. 

A number of rearrangements of alkyne ethers and sulphides on treatment with alkyllithium reagents are known, such as... 

Producing of Crystalline Aromatic Poly ketone with Simple Ether and Sulphide Linkages. Japan Patent Application 62-530. 

P. Dreyfuss and M. P. Dreyfuss, Polymerization of cyclic ethers and sulphides, in Comprehensive Chemical Kinetics, Vol. 15, Non-Radical Polymerization, C. H. Bamford, C. F. H. Tipper (eds.), Elsevier, Amsterdam, 1976. 

C.C. van de Sande, The mass spectra of ethers and sulphides. In The Chemistry of Ethers, Crown Ethers, Hydroxyl Groups and Their Sulfur Analogues, Suppl. E S. Patai, Ed. Wiley Chichester, 1980 p 2S>9. 

Reactions of Ethers.—In a recent report, allylic ethers (and sulphides, etc.) have been shown to be reduced to alkenes, with retention of the position and geometry of the double bond, by lithium triethylborohydride-Pd(PPh8)4. Deprotonation of propargyl ethers can be used to make allenic ethers and some a-substituted derivatives (Scheme 38). ... 

The synthesis of phenyl ethers and sulphides is carried out according to GL-PTC, introducing the mixture of the phenol (or thiol) and of the alkylating agent into the solid bed composed of (or NaHCO ) supporting Carbowax 6000 as schematized in equation 7. 

It will be seen that the oxygen group is chosen for suffix in example (d), but the sulphur group in example (e). This is because esters rank for priority immediately after their respective acids, so that for (d) carboxylate and not sulphonate is the principal functional group, and this is not altered because the systematic naphthalenecarboxylate is abbreviated to naphthoate however, ether and sulphide groups both rank after alcohols, phenols, and thiols— the rule in fact has considerable empiricism in its make-up. 

Sulphenates react with phosphines via the oxythiophosphorane R OPR 3SR, to give ethers and sulphides these results extend earlier studies. ... 

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