Ethers, unsaturated

Medium-ring cyclic ethers. Unsaturated eight- and nine-membered cyclic ethers can be obtained by cyclization of unsaturated acetals with SnCl4 (2 equiv.) in CH2C12. 

Organic peroxo compounds are also obtained by autooxidation of ethers, unsaturated hydrocarbons, and other organic materials on exposure to air. A free-radical chain reaction is initiated almost certainly by radicals generated by the interaction of oxygen and traces of metals such as copper, cobalt, or iron. The attack on specific reactive C—H bonds by a radical X" gives first R, then hydroperoxides, which can react further ... 

Reagents which effect epoxidation of the enol ether unsaturation effect a-hydroxylation comparable to the peracid approach. Thus a combination of molybdenum hexacarbonyl and r-butyl hydroperoxide converts the substrates to a-silyloxy derivatives. The peroxide generate in situ from benzonitrile, potassium carbonate and hydrogen peroxide can also perform the oxidation. Molybdenum-peroxy complexes, including MoOPH, could presumably also effect this transformation. Lastly, dimethyldioxirane has been used to epoxidize alkenes and it is likely that application of this useful, debris free, organic peroxide to these reactions will soon emerge. 

During heating to 150-220° C polyolefins isolate thermooxidative products of macromolecules with pronounced toxic properties, namely organic acids, ethers, unsaturated hydrocarbons, peroxide and carbonyl compounds (formaldehyde and acetaldehyde), carbon oxide and dioxide, etc. A mixture of such products of the thermooxidative destruction of polyolefins may result in acute chronic poisoning on inhalation. 

LiAlHa is normally unreactive toward ethers. Unsaturated acetals undergo reduction with double bond migration (Sn2 ) in cyclic systems, the usual stereoelectronic factors often apply (eq 5). Orthoesters are amenable to attack, giving acetals in good yield (eq 6) The susceptibility of benzylic acetals to reduction can be enhanced by the co-addition of a Lewis acid (eq 7). ... 

PC Bisphenol A, stilbenes, water, some organic pigments Chain scissions, crosslinks, free radicals, hydroxyl groups, ethers, unsaturations Chain scissions, hydroperoxides, free radicals, carbonyl groups... 

As in the case of diamino ethers, unsaturated thioanilines can be employed for template condensation with dap or 2,6-dfp. For example, 2,6-dfp and 1,2-bis(aminophenylthio)alkanes react in methanol or acetonitrile in the presence of some transition metal ions to form (1 -f-1) products L773-L775 (Eq. 3.64), isolated in the form of the respective complexes [138]. The macrocycle L773 is formed on manganese(II), zinc(II) and nickel(II) matrices and L774, L775 in the presence of zinc(II) ions. 

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