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Flavins as Biomimetic Catalysts for Sulfoxidation by H<sub>2</sub>O<sub>2</sub> : Catalyst Immobilization in Ionic Liquid for H<sub>2</sub>O<sub>2</sub> Oxidations

<p>This thesis deals with the development of catalytic oxidation reactions utilizing hydrogen peroxide as terminal oxidant. The main focus has been to find flavin catalysts that are easy to handle and stable to store but still able to perform the desired reaction. A variety of dihydroflavins were prepared and the electrochemical oxidation potentials were measured and compared with their catalytic activity.</p><p>A flavin catalyst was applied in the sulfoxidation of allylic and vinylic sulfides by H<sub>2</sub>O<sub>2</sub>. This transformation was highly chemoselective and the sulfoxides were obtained without formation of other oxidation products. The scope of the reaction was demonstrated by applying the method on substrates with a wide range of functional groups such as a tertiary amine. Another flavin catalyst was immobilized in the ionic liquid [BMIm]PF<sub>6</sub> and used for sulfoxidations by H<sub>2</sub>O<sub>2</sub>. The chemoselectivity was maintained in this system and the catalyst-ionic liquid system could be recycled several times.</p><p>Finally two bimetallic catalyst systems for the dihydroxylation of alkenes by H<sub>2</sub>O<sub>2</sub> were immobilized in the ionic liquid. These systems employed either vanadium acetylacetonate VO(acac)<sub>2 </sub>or methyl trioxorhenium (MTO) as co-catalysts together with the substrate-selective osmium catalyst. Good to excellent yields of the diols were obtained.</p>

Identiferoai:union.ndltd.org:UPSALLA/oai:DiVA.org:su-623
Date January 2005
CreatorsLindén, Auri
PublisherStockholm University, Department of Organic Chemistry, Stockholm : Institutionen för organisk kemi
Source SetsDiVA Archive at Upsalla University
LanguageEnglish
Detected LanguageEnglish
TypeDoctoral thesis, comprehensive summary, text

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