Synthesis and Applications of New N-Functionalised Iodine Compounds

In this thesis, the synthesis, characterization and application, in a series of model organic synthetic reactions, of N-coordinated iodonium(I) salts and N-functionalised hypervalent iodine(III) chlorides and fluorides is described.

In Chapter 2 the synthesis and characterization of novel N-coordinated iodonium(I) salts with multiple substituent groups based on IPy2BF4 is presented. Five-membered ring N-functionalised hypervalent Cl-I(III) and F-I(III) compounds are readily synthesized in excellent yields from para-substituted benzylamide compounds using TClCA and Selectfluor respectively. Their synthesis and characterization are compared with those of various O-functionalised hypervalent Cl-I(III) and F-I(III) compounds. X-ray crystallography reveals T-shaped geometries for these species and their structural data are compared with literature precedents. In Chapter 3 the applications of the new N-coordinated iodonium(I) salts in the iodination of aromatic compounds and iodocyclisation reactions are described. In Chapter 4 the applications of the new N-functionalised chlorobenzoiodazolone compounds as electrophilic chlorinating reagents in the chlorination of ethyl benzoylacetate and 1,3-diphenylpropane-1,3-dione, and the oxychlorination of styrene is presented. In addition, their reactivities are compared with those of two O-functionalised chlorobenziodoxolone compounds. In Chapter 5 the applications of the new N-functionalised fluorobenzoiodazolone compounds as electrophilic fluorinating reagents in the fluorination of 1,3-dicarbonyl compounds, the intramolecular fluorocyclisation of unsaturated carboxylic acids and the attempted geminal difluorination of α,α’-disubstituted styrenes is described, and their reactivities are compared with those of O-functionalised fluoroiodane. NMR studies in hexafluoroisopropanol reveal hydrogen-bonding between the fluorobenzoiodazolones and the solvent which may activate these compounds. Chapter 6 includes full experimental and characterization data for the chemistry outlined in Chapters 2-5.