We reported herein an efficient synthesis of l-allono-1,4-lactone from 2,3:5,6-di-O-isopropylidene-d-mannono-1,4-lactone in five steps. The key feature of this method involved a one-pot, ‘double inversion’ procedure at the stereocenters of C-4 and C-5 of d-mannono-1,4-lactone to afford the target molecule.