A polystyrene-supported triflating reagent for the synthesis of aryl triflates

An insoluble polystyrene-supported triflating reagent has been prepared by suspension co-polymerization of N-(4-vinylphenyl)trifluoromethanesulphonimide, styrene and the JandaJel ® cross-linker. This reagent, in the presence of triethylamine, allows for the efficient synthesis of aryl triflates from a wide range of phenols in a process that permits the desired product to be isolated from the reaction mixture in essentially pure form via several filtration and concentration operations. Adding to the utility of this reagent is its ability to be easily recovered, regenerated and reused. Both soluble and insoluble bifunctional polymers containing trialkylamine moieties in addition to triflimide groups were also prepared and examined as triflating reagents. Unfortunately these reagents afforded only modest yields of the desired products in representative reactions. Graphical Abstract. © 2004 Elsevier Ltd. All rights reserved.postprin

Reactions of nitroalkenes with nitroalkanes or sulfur ylides catalyzed by amine-thiourea bifunctional polymeric organocatalysts

Non-cross-linked and cross-linked bifunctional polystyrenes bearing both amine and thiourea groups have been synthesized and used as organocatalysts in reactions between nitroalkenes and nitroalkanes or sulfur ylides. Control experiments using monofunctional polymers with only either amine or thiourea groups attached indicated that both functional groups were essential for efficient catalysis of the reactions studied. The non-cross-linked polystyrene was soluble in typical organic solvents and was used as a homogeneous catalyst, while the cross-linked polystyrene was used as a heterogeneous catalyst. © Georg Thieme Verlag Stuttgart · New York.postprin

Rasta resin-DMAP and its use as a recyclable catalyst for the addition of carbon dioxide to epoxides

Rasta resin-DMAP, a new heterogeneous polystyrene-based amine, has been synthesized and used as a catalyst in addition reactions of carbon dioxide to epoxides to afford cyclic carbonate products. This new material was found to be a more efficient catalyst than divinyl benzene cross-linked polystyrene- supported DMAP, and was readily recovered and reused without significant loss of catalytic activity. © Georg Thieme Verlag Stuttgart - New York.postprin

Rasta resin-PPh3BnCl and its use in chromatography-free carbonyl cyanosilylation reactions

Rasta resin-PPhnCl, a new heterogeneous polystyrene-based phosphonium salt, has been synthesized and used to catalyze cyanosilylation reactions of aldehydes and ketones. It was found to be more efficient as a catalyst than a similar heterogeneous phosphonium salt anchored onto a polystyrene-based on the Merrifield resin architecture of 2% divinylbenzene cross-linking. In these reactions rasta resin-PPhnCl was separated from the desired reaction product simply by filtration, and it could be reused without significant loss of catalytic activity numerous times. © Georg Thieme Verlag Stuttgart New York.postprin

Synthesis of gamma-Sanshool and Hydroxy-gamma-Sanshool

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Chiral auxiliaries in polymer-supported organic synthesis

The use of chiral auxiliaries in polymer-supported organic synthesis is reviewed. In many of the examples presented, not only does the auxiliary serve as an element for inducing asymmetry into the synthesis, but it also functions as the linker for attaching the synthesis substrate to the polymer support. © 2003 Elsevier Ltd. All rights reserved.postprin

Multifunctional organic polymeric catalysts and reagents

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Polymer-supported thioanisole: A versatile platform for organic synthesis reagents

A new cross-linked polystyrene-supported thioanisole reagent is reported. This reagent incorporates the flexible JandaJel™ cross-linker and can be treated with methyl trifluoromethanesulfonate to form the corresponding sulfonium salt. This salt can in turn be deprotonated to form a polymer-supported sulfur ylide that is able to react with aldehydes and ketones to form epoxides. The thioanisole reagent can also be oxidized to form an insoluble sulfoxide reagent that is useful in Swern oxidation reactions. In these reactions, the polymer-supported thioanisole-based reagents can be recovered, regenerated and reused. © 2004 Elsevier Ltd. All rights reserved.postprin

Polyethyleneimine-Supported Triphenylphosphine and Its Use as a Highly Loaded Bifunctional Polymeric Reagent in Chromatography-Free One-Pot Wittig Reactions

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Catalytic Wittig and aza-Wittig reactions

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