A-Allyloxy anions

This in accordance with the mechanism shown in Figure 14.5. In a preequilibrium two 2-propoxide anions are replaced by a tertiary-butylperoxy anion and an allyloxy anion, as follows clearly from the kinetic equation. This intermediate has a very low concentration and has not been observed directly. From here on we can only speculate on the interactions leading to a preferred attack on either of the enantiotopic faces of the alkene. 

Anionic oxy-Claisen rearrangement.2 The [3,3] Claisen rearrangement of en-olates of a-allyloxy ketones is markedly dependent on the nature of the metal hydride used, and to a less extent, the solvent. An example is the rearrangement of a-(allyloxy)propiophenone (1) to the a-hydroxy ketone 2. The rearrangement... 

It has been demonstrated that the oxygen anion of initially formed product (36) effectively catalysed the [2,3]-Wittig rearrangement as a Lewis base. Other Lewis-base catalysts such as lithio or sodio 2-pyrrolidone promote the same [2,3]-Wittig rearrangement of silyl enolates generated from a-allyloxy ketones, whereas rearrangements of enolates from a-allyloxy esters were efficiently catalysed by ammonium 4-methoxybenzoate.24... 

For a more complex example of this type of rearrangement (anionic Claisen rearrangement of a tricyclic a-allyloxy ketone) see ref 108. 2-Allyloxy-3-methyl-2-cyclohexenones109 111 and nitrogen derivatives thereof112 rearrange in a different way. 

The hydrosilylation reaction has also been employed in the reverse way. A poly(dimethyl-siloxane) backbone exhibiting a number of silane (Si-H) functions is reacted with a polystyrene or a poly(methyl methacrylate) fitted at its chain end with allyloxy groups. The latter species can be obtained readily by reacting a living anionic polymer first with oxirane and then with allyl bromide. The hydrosilylation reaction yields poly(dimethylsiloxane- ra/t-styrene) or poly(dimethylsiloxane-graft-mQthyl methacrylate), which have been characterized as such. They exhibit typical behavior of thermoplastic elastomers over a rather broad range of compositions. ... 

Anionic galactomannans, which are derived from guar gum, in which the hydroxyl groups are partially esterified with sulfonate groups that result from 2-acrylamido-2-methylpropane sulfonic acid and l-allyloxy-2-hydroxypropyl sulfonic acid [1872], have been claimed to be suitable as thickeners. The composition is capable of producing enhanced viscosities, when used either alone or in combination with a cationic polymer and distributed in a solvent. 

Allyloxy)iodoarenes react with Sml2 to yield radical anions, which undergo thermal fragmentation. The resulting aryl radicals can cyclize to dihydrobenzofurans (Entries 8-10, Table 15.9). The radical obtained after cyclization can be reduced and treated with a proton source such as water or an alcohol to yield alkanes, or with carbonyl compounds to yield alcohols (Entry 10, Table 15.9). 

Wu and coworkers studied the silica-nanoparticle-stabilized emulsion polymerization of vinyl acetate, with the aid of a small amount of anionic reactive surfactant, 3-allyloxy-2-hydroxy-l-propanesulfonicacid sodium salt (HAPS) [118]. They argued that hydrogen bond interactions allowed for strong adhesion, and also commented on the mechanism of solids-stabilized emulsion polymerization. 

Synonyms Alkanesulfonic acids, sodium salts Sodium alkane sulfonate Uses Antistat used in plastic and rubber compounds solubilizer, welling agent, hydrotrope in shampoos, all purpose cleaners Regulatory Canada DSL Trade Names Avitone A Sodium allyloxy hydroxypropyl sulfonate Synonyms Sodium 1-allyloxy-2-hydroxypropyl sulfonate Ionic Nature Anionic Empirical CgH -NaOsS Formula CH,=CHCH20CH2CH0HCH2S03Na Properties M.w. 218... 

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