Synthesis of non-natural cyclic amino acids from available unsaturated tertiary amines

Article abstract of DOI:10.1134/S1070428010090022

New approach is developed to the synthesis of cyclic amino acids derivatives. Unsaturated tertiary amines react with ethyl diazoacetate under the catalysis by copper catalyst Cu(F₃acac)₂ leading to the formation of products of [2,3]-sigmatropic rearrangement which via the metathesis of double bonds undergo a ring closure. The subsequent hydrogenation of compounds obtained furnished esters of 6- and 7-membered cyclic α-amino acids. Besides the racemic also optically active compounds were obtained, in particular, esters of (R)- and (S)-pipecolic acid.