Recent important propress in iring-closing metathesis of olefin is reviewed. The ring-closing metathesis recently emerges as a powerful method for the synthesis of a variety of ring systems including carbo-, and heterocycles, and has found extensive applications in the synthesis of natural products. These reactions are atom economic and meet the requirementsof green chemistry.

Key words: ORGANIC SYNTHESIS, DOUBLE BONDS, DOUBLE DECOMPOSITION, RING CLOSURE REACTION, BENZOPYRAN, AMINO ACID, PEPTIDE, LACTAM, SULFONIC ACID AMIDE, PHOSPHOROUS HETEROCYCLIC COMPOUNDS