Synthesis of (2R, 5S)- and (2S, 5S)-2-carboxy-1,4-diaza-[4.3.0]bicyclononane as building blocks for the synthesis of new potential HIV protease inhibitors
A procedure for the preparation of optically active (2R,5S)- and (2S,5S)-2-Carboxy-1,4-diaza-[4.3.0]bicyclononane is described. The method is based on the reduction of diketopiperazines obtained from cyclization of Pro-L-Ser or Pro-D-Ser and occurs without loss of enantiomeric purity. The synthesis is based on readily available starting materials and can be easily arranged for multigram scale preparations. Copyright (C) 1996 Elsevier Science Ltd