Novel Developments in Halogenation Reactions

摘要

Halogenation chemistry is one the most important transformations in organic synthesis. It has been studied for decades using from the most straightforward, inexpensive elemental halogens or hydrogen halides to catalysts, which can proceed via catalytic chemo-, stereoselective halogenations. Chemists continue to seek novel methods of halogenation reactions due to their importance in synthesis as reactive intermediates and targets.;Four parts are discussed in the thesis. The first part introduces vanadium-mediated Meyer--Schuster reaction. In this part, the properties of general vanadium complexes and background of Meyer--Schuster reactions are described. The second part outlines the second project related to the metal-free dichlorination reaction using m-CPBA and SOCl2. This method is complementary to existing dichlorination methods. The third part and fourth part are related to fluorination reactions. In the third part of this thesis, fluorination of tertiary carbon centers next to ketones and esters is discussed and a mechanism is proposed. In the last part, a novel difluorination of benzofurans is presented.