Metathesis Reactions

Modern synthetic organic chemistry has sufficient flexibility to construct acyclic compounds selectively rather than aromatic compounds. Therefore, the direct construction of aromatic rings from acyclic precursors would provide one possible solution to the difficulty of responding to the growing demand for complex aromatic compounds. Combinations of the cyclization of acyclic precursors prepared in a selective manner and subsequent aromatization provide effective means to access the aromatic compounds desired without the formation of inseparable regioisomers. This chapter presents representative synthetic examples of aromatic compounds using ring-closing metathesis (RCM), divided into several types of methods. The chapter discusses methods such as alkene metathesis, and ene—yne metathesis. Since RCM has become one of the most powerful cyclization reactions, great possibilities can be expected in this field.