Scavenging reagents

NA Sole, G Barany. Optimization of solid-phase synthesis of [Ala8]-dynorphin A1 3, (scavenger Reagents B, K, R) J Org Chem 57, 5399, 1992. 

Kaldor [49 i, 55] demonstrated the advantages of applying solid-supported scavengers to the preparation of parallel arrays in a multi-step fashion. In these studies he examined the clean-up of multiple amine alkylation and acylation reactions using a variety of immobilized electrophilic and nucleophilic scavenger reagents including an amine, isocyanate, aldehyde and acid chloride (Tab. 2.1). 

Alkoxysilanes are frequently used as scavenger reagents for silenes. They add regiospecifically to the Si=C bond. In the case of silacyclobutadiene 296 the reaction was shown to be also stereospecific. Thus Z-404 is the sole product of the addition of trimethylsilyl methyl ether (TMSOMe) to 296 (equation 122)163. Characteristically Brook -type silenes do not react with alkoxysilanes like TMSOMe. 

A different approach to 2-silallenes was utilized by Auner and coworkers232. They found that in the reaction of dichlorodivinylsilane and 2 equivalents t-BuLi, highly reactive intermediates are formed, which could be trapped with suitable scavenger reagents like anthracene, TMSOMe and norbornadiene (equation 219). 

Other representative examples in which polymeric scavenger reagents are used, include L. A. Thompson and J. A. Ellman, Chem. Rev. 1996, 96, 555-600 ... 

Combined with expedient purification techniques (e.g., scavengers, reagents on solid support, and solid phase extraction techniques) [ 14], microwave-assisted synthesis is leading the way towards genuine high-throughput chemistry that will hopefully ease the chemistry-related bottleneck in the drug development process. 

Recently, a number of publications have dealt with the synthesis of drug-like molecules via fully automated PASP (auto-PASP) synthesis. This scenario entails the use of a series of immobilised reagents and scavenger reagents to perform a variety of sequential synthetic transformations in a common solvent. Each of the transformations... 

Polyhydric alkanols required an excess of tellurium hexafluoride to hold the reaction at the stage of the alkoxy tellurium pentafluoride. Sodium fluoride was used as the HF-scavenging reagent. ... 

The addition of hydrido complex-scavenging reagents would be expected either to reduce the reagent (19, 20) (Reaction 14) or to form a stable organocobalt complex (22) (Reaction 15), depending on the re-... 

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