A,/?-epoxy silanes

Titanium(IV) isopropoxide, 311 a,(3-Epoxy aldehydes and ketones Fluorine-Acetonitrile, 135 Oxodiperoxymolybdenum-(pyridine)(hexamethylphosphoric triamide), 227 a,(3-Epoxy silanes Allyltriisopropylsilane, 11 m-Chloroperbenzoic acid, 76 Esters (see also Dicarbonyl compounds, Unsaturated esters)... 

Basis and Example of Use. This reagent acts as the alkyla-tive equivalent of 3-buten-2-one (methyl vinyl ketone), permitting regiospecific enolate alkylation under nonequilibrating conditions. As a vinylsilane it can be converted, via the corresponding a,/3-epoxy silane, into a 3-oxobutyl moiety, and hence used in an alkylative equivalent of Robinson annulation. Application of such methodology can be seen (eq 1) in the preparation of bicyclodecenones via the alkylation of dihydrocarvone with this reagent. Apart from this application, and its use in combination with potassium iodide, it has seen little use so far. 

Reaction of a, fi-epoxy silanes with organocuprates. Hudrlik et al have shown that the reaction of di-n-propylcopperlithium with o , 3-epoxysilanes is both regio- and stereospecific. Thus the cii-epoxide (1) is converted into the erythro-alcohol (2), whereas the franr-epoxide (3) is converted into the threo-alcohol (4). ... 

Trimethylsilylstyrenes are formed by reaction of alka-nesulfonyl chlorides with TMSCHN2 in the presence of triethyl-amine (eq 13). TMSC(Li)N2 reacts with carbonyl compounds to give a-diazo- -hydroxy silanes which readily decompose to give O, /3-epoxy silanes (eq 14). However, benzophenone gives diphenylacetylene under similar reaction conditions (eq 15). ... 

Foam compositions, including a latex and a polynitrile oxide such as 2,4,6-triethylbenzene-l,3-dicarbonitrile oxide, or a latex and an epoxy silane, or a latex and a mixture of the two crosslinkers have been prepared (526). The compositions may also contain additional components, including fillers, surfactants, cell detackifiers, froth stabilizers, froth boosters, viscosity reducers, and compounds to improve resilience, and antioxidants. The compositions are particularly useful in the manufacture of flooring, wall covering, shoe lining and nonwoven materials. 

FIGURE 4.3 Images of the fractured surfaces of the cured compositions at 20,000x magnification (AURIGA CrossBeam) (A) epoxy-silane-amine composition, (B) neat epoxy-amine composition. (Reprinted from E. Delebecq, J-P. Pascault, B. Boutevin, and F. Ganachaud, On the Versatility of Urethane/Urea Bonds Reversibility, Blocked Isocyanate, and Non-Isocyanate Polyurethane, Chem. Rev. 113 (2013) 80-118. With permission.)... 

Allyl glyddyl ether is a monoglycidyl derivative, used as a reactive epoxy diluent for epoxy resins. As an impurity, it was considered as the sensitizing agent in a plastic industry worker allergic to 3-glycidyloxy-propyltrimethoxysilane, an epoxy silane compound used as a fixing additive in silicone and polyurethane. 

In an interesting and nnnsnal reaction, Paquette and Maynard have shown that peracid oxidation of l,2-disilyl-3,3-dimethylcyclopropene gives rise to an a -silyl-a, -unsaturated acyl silane, throngh rearrangement of the intermediate epoxycyclopropane. Further treatment with peracid gave the a-epoxy acyl silane (Scheme 54)... 

The amount of silane and triethylamine used should be approximately proportional to the surface area of the silica thus, if a silica of 50 m /g is coated then five times less reagents should be used. The epoxy group concentration on coated silica can be determined by titration of the hydroxyl ions released during the reaction of the epoxy groups with thiosulphate (4). To do this suspend up to 100 mg of dry epoxy-silica in 2 ml water and adjust the pH to 7.0. Add 1 ml of a 3 M solution of sodium thiosulphate, pH 7. 0, to initiate the reaction. During the course of the reaction ( — 60 min) maintain the pH at 7.0 by adding 0.1 M HCl. The consumption of HCl corresponds to the epoxy group content of the gel. 

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