Ita Hajdin

• Diazo compounds are remarkable versatile building blocks and increasingly important molecules in organic synthesis. Even though the field of diazo chemistry was discovered more than hundred years ago it is still a subject of great research interest. Besides, the field of organofluorine chemistry has grown immensely in recent years, and fluorochemicals have permeated into nearly every aspect of our daily lives. Hence, the aim of this work was the synthesis of a bench-stable 2-diazo-1,1,3,3,3-pentafluoropropyl phosphonate, the first fluorinated diazo compound bearing trifluoromethyl and difluoromethyl phosphonate moiety, along with a demonstration of its synthetic applications in a series of chemical reactions. After the successful synthesis, the novel diazo compound was incorporated in cyclopropanation reaction of aromatic and aliphatic terminal alkenes using CuI as a catalyst. Consequently, sixteen new cyclopropanes were synthesized in good to very good yields and under mild reaction conditions. Furthermore, a new pathway for synthesizing fluorinated β-alkoxy vinyl phosphonates via O-H insertion reaction using Rh2(OAc)4 as a catalyst is presented in this thesis. The insertion reaction of benzyl and aliphatic alcohols using the diazo compound were carried out under mild conditions and nineteen new fluorinated β-alkoxy vinyl phosphonates were synthesized in good to very good yields. The following reaction was a catalyst- and solvent-free 1,3-dipolar cycloaddition of alkynes and alkene with the diazo compound. This green approach provided an efficient route for direct synthesis of fluorinated pyrazoles and pyrazoline in moderate to excellent yields. Lastly, a Cu(II) catalysed [2,3]-sigmatropic rearrangement reaction of propargyl and allyl sulfides with the diazo compound produced products bearing difluoromethylphosphonate and trifluoromethyl groups.