Synthesis of Macrocyclic -Peptidomimetics by Ring-Closing Metathesis

The synthesis of a series of conformationally constrained peptidomimetics containing a 9-to-13-atom-membered ring by ring-closing metathesis (RCM) is described. The second-generation Grubbs catalyst proved to be the most effective in producing the desired cyclic beta-peptidomimetics with moderate to good yields. Reaction characteristics such as the influence of alkene chain length in the precursors, position of double bond and ring size of products were also discussed.