Synthesis of Macrocyclic β‐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 β‐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. In this paper, a series of macrocyclic peptidomimetics from 9 to membered‐ring containing 2 beta‐amino acid unit have been synthesized by using ring‐closing metathesis reaction. All cyclization succeeded with full conversion and no detectable by‐product. Present work opens up new opportunities to discover more structural variants of peptidomimetics which can serve as a valuable addition to chemical biology and drug design.