Polystyrene resins bromomethyl

Ellman used silyl chemistry for the direct linkage of aromatics onto the solid support by converting an aryl bromide to aryl lithium and reacting this with a silyl resin.90 It is the production of the silyl resin that is of interest in the context of this review, since an in situ Suzuki coupling was used to link the allyl silane to bromomethyl polystyrene resin (Scheme 40). 9-BBN is used to carry out the regioselective hydroboration, and this is linked to the resin with palladium catalysis in the usual way. After brief exposure of this... 

A suitable [3-ketoester was first converted into the corresponding 2-mercaptopyrinii-dine by employing a microwave-assisted, EtONa-mediated condensation with thiourea in EtOH/DMF (10 1) at 130°C for 30min. The obtained compound was then attached to bromomethyl polystyrene resin at 100°C, once again under microwave irradiation for 10 min (Scheme 8.22). The amide group was then subjected to a TEA-mediated alkylation using 2-bromoacetonitrile in a 10 1 mixture of DMF and EtOH at 120°C for 20 min under... 

Attachment of the catalyst to a polymeric support can also be facilitated using a bis-carbene as the ligand [253]. The bisimidazoUum salt featuring a hydroxyalkyl sidechain on each of the two imidazolium units was reacted with palladium (II) acetate to form the neutral catalyst complex (see Figure 4.82). Immobilisation was then achieved by reacting the functionalised catalyst with 4-(bromomethyl)phenoxy-methyl polystyrene, known as Wang resin, as the polymeric support. 

The SM reactions are eompatible with the solid-phase synthesis what is applied in the combinatorial chemistry [95,97]. The arylboronic acids can be immobilized on the polystyrene eontaining diethanolamine-moieties by forming boronate esters XXV. A wide variety of thus bounded arylboronic acids bearing a bromomethyl, carboxylic, amino or aldehyde-group have been converted by N- or O-alkylation, amidation, reductive alkylation and some other reactions, to amines, esters, amides, ureas, etc [96]. The resulting arylboronic acid can be regenerated from the resin by simple... 

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