Utilization of 1,3-Dipolar Compounds

This chapter reviews transition-metal-mediated synthesis of aromatic (mainly heteroaromatic) compounds using various 1,3-dipoles. A number of transition-metal-mediated 1,3-dipolar cycloaddition reactions have been applied successfully in the synthesis of complex natural products and biologically active heterocycles. In addition, the transition-metal-catalyzed decomposition of 1,3-dipoles including azides, diazoalkanes, carbonyl ylides, and azomethine ylides for the generation of highly reactive species (e.g., carbenoids, nitrenoids, iminyl radicals, iminyl metal species) with concomitant release of dinitrogen has exploited new applications of 1,3-dipoles for the construction of aromatic components. The development of novel 1,3-dipoles as well as exploration of their unprecedented chemical reactivity, especially with transition metals, will certainly be important challenges for the synthesis of various aromatic compounds in the future.