Tetra-n-propyl ammonium perruthenate in the presence of morpholine-N-oxide induced the unanticipated transformation of the epimeric a-azido-1, 4-lactones 4 into the bicyclic amine 3 and provided the key step in the synthesis of 5-epihydantocidin 2. Brief investigations into the acid catalysed equilibration of hydantocidin 1 and 5-epihydantocidin 2 are described.
