Access to Cyclic -CF3-Substituted -Amino Acid Derivatives by Ring-Closing Metathesis of Functionalized 1,7-Enynes

An efficient method for the preparation of new -CF3 -amino acid 1,7-enynes that contain electron-donating and electron-withdrawing groups on the triple bond has been developed that proceeds through a Sonogashira-type coupling reaction. The ring-closing enyne methathesis (RCEYM) of the obtained 1,7-enynes with commercially available Grubbs and Hoveyda catalysts provides access to a series of new cyclic -amino acids. The latter compounds that contain the 1,3-diene moiety are attractive building blocks for the construction of trifluoromethylated polycyclic systems.