Polyhydroxyamino-Piperidine-Type Iminosugars and Pipecolic Acid Analogues from a D-Mannose-Derived Aldehyde

A general strategy for the synthesis of diversely substituted 3,4,5-trihydroxypiperidines (including two natural products), 5-amino-3,4-dihydroxypiperidines, 3,4,5-trihydroxypipecolic acids, and 2-(aminomethyl)-3,4,5-trihydroxypiperidines is reported. The procedure used a double reductive amination or a Strecker reaction, starting from differently protected aldehydes readily synthesized on a gram scale from D-mannose. The biological activities of the target compounds were evaluated, and some of them showed moderate inhibition of α-L-fucosidase and β-glucosidase.