Chlorosilane, Polymer-supported

Subsequent treatment with l,3-dichloro-5,5-dimethyl-hydantoin in THF provides the Rasta-(diisopropylchlorosilyl) TEMPO methylpolystyrene resin (eq 4).  

Preparative Methods lithiated polystyrene can be prepared via direct lithiation of cross-linked polystyrene with (1 1) BuLi and TMEDA at 65 °C in cyclohexane (eq 1)T Subsequent addition of diisopropyl-dichlorosilane in benzene followed by washing with excess benzene and drying in vacuo provides the desired functionalized polymer. Loading can be determined by hydrolysis and acid-base titration.  

Handling, Storage, and Precaution reagent is water sensitive and cannot be stored for prolonged periods. 

DusopropylsUyl linkers on polystyrene resins have been used in solid-phase synthesis of oligosaccharides and glycoconjugates via the glycal assembly method (eq 6).  

Diisopropylsilyl linkers are more stable to glycosyla-tion conditions than their diphenyl counterparts. Rasta-(diisopropylchlorosilyl) TEMPO methylpolyst3rene resins have been demonstrated as viable polymeric supports (eq 7), however, the increased complexity of their preparation from commercially available starting materials has thus far precluded broader general application. 

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Cl(i-Pr)2Si C6H4-/p-Poly Diisopropyl Chlorosilane, Polymer-supported No CAS 240... 

In addition, the asymmetric reduction of A7-aryl ketimines with tri-chlorosilane could be achieved on polymer-supported organocatalysts by Kocovsky et alP Indeed, 7V-methylvaline-derived formamide anchored to a polymeric support, used at a catalyst loading of 15 mol %, allowed good enantioselectivities of up to 82% ee combined with good yields to be obtained for the formed chiral amines (Scheme 8.3). This novel methodology simplified the recovery of the catalyst, which could be reused at least five times without any loss of the activity. The best results were obtained with the catalysts directly attached to the polymer or via a suitable spacer. A strong influence of the solvents on the catalytic performance was observed with chloroform giving the... 

Next to ion exchange resins, the polymeric supports most likely to be used for catalysts are other cross-linked polystyrenes or silica gels. Both are inexpensive, easy to functionalize, and void of other reactive functional groups. Their limitations are the thermal and physical stability of polystyrene and the solubility of silica in alkali. Polystyrene can be derivatized by almost every known reaction of mononuclear aromatic hydrocarbons, and the conditions for those reactions on polymers have been published and reviewed (2D- The surface of silica gel can be covered with a wide range of organic materials by reaction of its hydroxyl groups with silyl esters and chlorosilanes f381. 

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