aldehyde with the D-lyxo configuration is a versatile key intermediate to functionally and stereochemically diversified piperidines. It allowed the synthesis of natural 3,4,5-trihydroxypiperidines and new analogs through a double reductive amination strategy and the synthesis of novel 2-cyanotrihydroxypiperidines through a highly regio- and diastereoselective Strecker reaction.