Synthesis of pyridines with an amino acid residue by [2+2] cycloadditions of electron-poor acetylenes on enaminone systems derived from N -Boc protected amino acids

In this paper we present a pyridine synthesis, starting from N-protected amino acids. Amino acids are firstly converted to an ynone system, which is later converted to an enaminone system. Following a formal [2 + 2] cycloaddition of electron poor acetylenes and subsequent ring closure the final products are pyridines bearing an amino-acid substituent.