Synthesis of macrocyclic compounds by ring closing metathesis

Synthesis of macrocyclic compounds including natural products with varying complexities by ring closing metathesis is described. Twelve to very large rings that have been synthesized in moderate to good yields and the synthesis of larger rings as a part of bi- or poly-cyclic systems are also described in this review. The effectiveness of the Grubbs' catalyst towards the RCM in presence of free alcohols, epoxides as well as with various silyl ethers is also presented. In addition to these, the application of RCM towards the syntheses of various naturally occurring macrolides, lactams and unnatural cyclic poly ethers, catenanes etc. are described.