Synthesis of fluorine-containing cyclic amino acid derivatives via ring closing olefin metathesis

New N-protected α-CF3 amino esters with two alkene chains (1,7-dienes 3 and 1,6-dienes 5) were reacted with the ring closing metathesis catalyst RuCHPh(Cl)2(PCy3)2 to give the α-CF3 dehydropipecolinate and prolinate derivatives 6 and 7.