The title compound, C59H56ClN3O16, is an important dissacharide precursor to novel therapeutics for the treatment of Alzheimer's disease. It crystallizes with two independent enantiomerically identical molecules in almost exactly the same orientation in the cell, being one half cell-edge apart. Apart from the conformation of a single benzyl group, the molecules are superimposable. They are bound efficiently using complementary C-H···O(carbonyl) hydrogen bonds, principally along the `duplicating' axis. The absolute configurations were determined.