Synthesis of trans-4-Triazolyl-Substituted 3-Hydroxypiperidines

The synthesis of tert-butyl trans-4-ethynyl-3-hydroxypiperidine-1-carboxylate is described via regioselective ring-opening of a racemic N-Boc-protected 7-oxa-3-azabicyclo[4.1.0]heptane, and serves as a new scaffold for the preparation of substituted piperidines. The terminal alkyne is converted into 1,4- and 1,5-disubstituted 1,2,3-triazoles through 1,3-dipolar cycloaddition reactions with organic azides.