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

An efficient method for the preparation of new α-CF3 α-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 α-amino acids. The latter compounds that contain the 1,3-diene moiety are attractive building blocks for the construction of trifluoromethylated polycyclic systems.