Homologation Reactions for the Synthesis of Fluorinated Molecules

Fluorinated diazoalkanes are important building blocks, which could provide accesses to versatile fluorinated densely functionalized small molecules. This book chapter will provide an overview of the different transformation of fluorinated diazoalkanes, including cycloaddition reactions, insertion reaction, gem -difluoroolefination reactions, and other reactions. (1) Cycloaddition Reaction of Fluorinated Diazoalkanes Cyclopropanation reactions and dipolar cycloaddition reactions are summarized in in this chapter. Different fluorinated heterocycles, such as pyrazolines, isoxazoles, and triazolines, could be easily obtained from fluorinated diazoalkanes with unsaturated system catalyzed by various transition-metal catalysts. Highly diastereo- and enantioselective construction of trifluoromethyl-substituted cyclopropane could be realized by using myoglobin. (2) Insertion Reactions Insertion reaction of fluorinated diazoalkanes with CH/XH or XY bond could easily introduce the C1 unit. This subchapter will outline recent achievements by utilizing fluorinated diazoalkanes with various CH/XH or XY bond. (3) gem -Difluoroolefination Reactions gem -Difluoroolefin is geometrical isoster of carbonyl groups, which could effectively approve the bioactivity of drugs. Recently several groups successfully developed the directly gem -difluoronation reaction from fluorinated diazoalkanes or fluorinated tosylhydrazone.