The application of solid phase extraction in organic synthesis using fluorous derivatised metal catalysts
thesisposted on 15.12.2014, 10:35 by Ben Croxtall
This thesis describes the synthesis, characterisation and coordination chemistry of a variety of fluorinated ÃŸ-diketonate ligands (I) and carboxylate ligands (II), the catalytic activity of the resultant metal complexes for oxidation and C-C bond forming reactions, and an evaluation of fluorous methodologies for catalyst/product separation. (Fig. 3706) Chapter 1 introduces the concept and application of fluorous methodologies, including fluorous biphase catalysis and fluorous reverse phase silica gel (FRPSG), as alternative approaches to product/catalyst separation in homogeneous catalysis. Chapter 2 describes the synthesis and characterisation, in some cases by X-ray diffraction, of the fluorinated ÃŸ-diketonate ligands and an evaluation of the influence of the perfluoroalkyl groups on the coordination of these ligands to a variety of transition metals including copper, nickel, palladium and zinc. Chapter 3 outlines attempts to sue fluorous nickel ÃŸ-diketonate complexes for the oxidation of sulfides. The results indicate that a metal catalyst is not necessary for oxidation in this system although the veracity of catalyst separation using FRPSG was established. This chapter also describes the investigation of a fluorous molybdenum ÃŸ-diketonate complex for the oxidation of alkenes, although the extreme moisture senstiviity of the complex negated any attempts at recovery and recycling. The scope of Lewis acid catalysed coupling of ÃŸ-diketones with cyanoformates and the ability to reuse and recycle the fluorinated ÃŸ-diketonate catalysts is described in chapter 4. Chapter 5 describes attempts to extend this efficient separation procedure to the C-C bond forming reactions of rhodium carboxylate dimers. Although catalysis was observed, catalyst/product separation using FRPSG was unsuccessful. Chapter 6 summarises all the experimental details and spectroscopic data, whilst a CD-rom includes all of the crystallographic data.