An Improved Stereoselective Synthesis of L-Alanosine

An improved, stereoselective synthesis of the natural, nonproteogenic amino acid L-alanosine has been developed, starting from the readily available and cheap substrate L-serine, in six steps and 49% overall yield. The process is very efficient, is suitable for large-scale production, and affords Lalanosine with properties comparable with those of the natural substance. In addition, the structural assignment concerning some previously reported synthetic alkylated derivatives of the natural amino acid has been definitively confirmed.