A NOVEL METHOD OF CYCLIZATION BY MEANS OF ALKENE METATHESIS - A SYNTHETIC STRATEGY OF CARBOCYCLIC-COMPOUNDS AND HETEROCYCLIC-COMPOUNDS

Historical background of alkene metathesis is briefly reviewed. The in troduction of the Schrock Mo carbene complex and the Grubbs Ru-carbene complexes has initiated rapid development of synthetic utility of alk ene metathesis. Many functional groups are tolerated without protectio n in the Mo and Ru catalysed metathesis. Among several synthetic appli cations of the alkene metathesis, the ring closing metathesis offers a n extremely useful method for cyclization to give carbo- and hetero-cy clic compounds from medium to large sizes. A number of naturally occur ring macrocyclic compounds have been synthesized in shorter steps by t he ring closing metathesis using the Ru complex as key reaction. The a lkene metathesis has brought in a dramatic change in synthetic designs of complex cyclic compounds.